Misfire Diagnostics P0300 GM

[@mark97213]

One of the nicest, most informative and visually informative ignition videos I've ever seen. Thank you.

[@robertpayne5499]

This is the most informative ignition video I have seen. My 5.7 vortec goes through cap and rotors all the time. Finally saw this video and noticed my "vent" holes where in the casting but never drilled from the factory! Also the timing light trick, checked all wires and had a double fire on 4 meaning it was stealing from Some where, never thought of that trick.

[@tedeisner822]

very concise and informative, thank you. i learned more from your 7 min video than hours combined of others. earned my subscription instantly

[@GoTechTraining]

Hey Ted, thanks for watching! Mike Becker, Senior Instructor

[@stevelouissilva458]

You guys are the most descriptive and just plain out in most fun awesome dudes when it comes to KZbin videos about vehicles maintenance

[@jimmyb2480]

Thanks for the info, I have a 2000 GMC Jimmy 4X4 4.3 with 215,000 kms, it was running very ruff, and would hardly start or accelerate,I checked the code with my OBD II reader and got the dreaded PO300 I replaced the plugs with NGK and the plug wires AC Delco, it helped a little bit, I found your video on You Tube and I changed the distributor cap and rotor and now she runs like new, just awesome thanks for your video it sure helped me. p.s. I'm 58 years old and have owed over 20 different vehicles and I have never put so much money in repairs to a car or truck as I have with this one, NEVER AGAIN GM. I've learned my lesson.

[@GoTechTraining]

James Bothwell Hey Jim! Thank you for the great testimony! If you need anything just ring.Mark Hicks Wells Vehicle Electronics

[@Nudnik1]

James Bothwell Have 350k and 250k on my GM 5.3 and 4.3 no issues run like new.

[@briansmobile1]

Great visuals and training on O3 and condensation evacuation. Sorry you blew up at 6:59. Get Wells soon!

[@GoTechTraining]

Hey Brian, How are things these days? It was my boss I blew up there! One of my favorite things about my job :). Thank you for the kind words, this one was a blast to put together. Take care my friend, Mark Hicks Wells Vehicle Electronics

[@klb1956]

Thank you for this informative video. Just replaced heads on a 2002 Buick Rendezous 3.4. Using remanufactured heads, replacing plugs, wires, water pump, thermostat, water hoses and anything else as preventative maintenance to keep from tearing into this thing again. The initial problem was water in the oil, assuming it was a head gasket. Once all back together the Check Engine light was on. The code of PO300 came up as a random misfire. After checking the firing order, I used your method of attaching a timing light to each plug wire looking for the misfire. I was able to locate and determine a bad coil. A trip to the yard and I was back in business, no more PO300. Thank you for saving me from pulling anymore hair out as I would be bald!

[@GoTechTraining]

+Keith L Beaubien Glad to hear you were able to get it fixed without going bald! :) It's a great test procedure. Mike Becker, Technical Services Instructor

[@GoTechTraining]

Thank you! Your kind words mean a lot to us! Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

Thank you for the kind words. It was a lot of fun putting it together too. Stay tuned we have some cool stuff coming in the future. Your comment truly means a lot to us! Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

Thank you George! Always like hearing from you too! We truly appreciate your support. Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

I will always be here. Sorry for the delay. I do a lot of stuff for Wells and our customers we don't post on KZbin. Hope you liked this one. It was a blast to put together. Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

Thanks for the kind words, they truly mean a lot to us! Mark Hicks Wells Vehicle Electronics

[@ChaplainMike777]

awesome video! I have been having that problem p0300. I cleaned that vent hole once before - it was clogged. I think I need to take a better look because it appears I missed a second vent hole. Thank you for the great video. Very well done!

[@GoTechTraining]

Hey, thanks for watching Mike! ~Mike

[@GoTechTraining]

Thanks! I miss you guys too! Glad you liked the video. Mark Hicks Wells Vehicle Electronics

[@jeffcampbell4866]

Top shelf buddy. The graphics and your explanations are just TOP SHELF!! Thanks

[@GoTechTraining]

Hey Jeff thanks for watching! Ryan W, Technical Instructor

[@E9859-v7d]

Not only did you take the time but went through the why's and how's, simplicity!

[@GoTechTraining]

Thank you Edwin, your words are much appreciated and mean a lot to us. We give it our best. Take care my friend, Mark Hicks Wells Vehicle Electronics

[@E9859-v7d]

RIGHT ON!

[@ericthecarguy]

Nice video! I wish I could fit inside my distributor cap.

[@GoTechTraining]

Greetings Malisa! Thank you for the kind words. When we started this project it was a real challenge to figure out how we were going to get the message of moisture and ozone across. Your comment could not be more satisfying to us. Mark Hicks Wells Vehicle Electronics

[@jesusonewilmas]

Great video I love the timing gun idea

[@GoTechTraining]

Hey thanks felplay! Always nice to hear from you. Take Care my friend, Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

Hey Eric! A comment like this coming from you I feel humbled. Thank you it means a lot to us! When you come up to visit the next I will make sure you will fit inside the cap :) Talk with you soon my friend, Mark Hicks Wells Vehicle Electronics

[@malisa696]

great video and it was very good understanding how moisture and ozone are made inside the distributor cap. Greetings from Serbia, Europe.

[@GoTechTraining]

Thanks for the kind words. I checked out Dan's channel, he does a great job! Thanks for the suggestion. Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

Thank you for the great comment Chris! I think GM was trying to remove as much weight as possible. Personally I feel this is not the place to do it. But I can understand it with all the pressures they get from government agencies. You are right be careful turning the screwws into the plastic. Take Care, Mark Hicks Wells Vehicle Electronics

[@dukeman7595]

I like your video, it was concise and lucid with the DIY in mind . You explained all the points in a simple well thought out process. I am very impressed, and now a new subscriber.

[@GoTechTraining]

Welcome aboard Joseph! We appreciate your kind words. We do the best we can. God Bless, Mark Hicks Wells Vehicle Electronics

[@drwombat]

I just watched a few of your videos and this is an excellent channel you and your team ARE some REAL technicians just like you mention at the beginning of this video

[@GoTechTraining]

+drwombat Thank you, we appreciate the kind words. We are all master techs with years of shop experience, so we know what it's like to be in a shop. By doing these videos we hope that we can make everyone's day a little bit easier. Mike Becker, Technical Services Instructor

[@drwombat]

+markjhicks quick question and I know this is probably important but last time I checked my suppression wires for ohms I simply probed and re probed I noticed your tech is wriggling the wires back and forth twisting them about then and only then does the resistance jump to higher than acceptable levels why do you think that is? this is a technique I will have to remember to borrow on my next diag

[@markhicks4236]

+drwombat Yes, it is important to move the wires around some when you are testing resistance. When the ignition wires are on the engine and it is running at different RPM, the wires will vibrate and shake. It is common for an issue with the ignition wires not to show up until they are jostled. Great question! Thank you! In our next video on the subject we will be sure to make note about proper testing. Mark Hicks Wells Vehicle Electronics

[@drwombat]

+Mark Hicks I believe I found your channel thru a sponsorship on another channel. I'm glad I realized you had your own as this information is much more my speed. I hope to be a part of the next live session for a chance to win a coveted t shirt

[@GoTechTraining]

+drwombat Good, we will see you at our next broadcast on Thursday the 21st hopefully! Mike Becker, Technical Services Instructor

[@kiefferbrothers1567]

Thanks for the info in the video. I ran across an unusual P0300 code on my 03 S10 with 4.3 . I replaced the distributor at 149K miles Dec 4,2015 because of worn bushings. I could have put in reman nylon body units ,but I found a new Alum body unit and it even came with new cap and rotor for about $20 more. Now is when it gets interesting, 375 miles later my engine just dies going down the road at 60mph, no warning or nothing. Pop the cap off and found center tab broke off of rotor, and also burnt thru on bottom of rotor, put handy used one on, I keep with me. Took bad rotor to supplier and was given a new one off of another new Dist. "Great they stand behind their parts,He HE He!" Fast forward to Dec 29 2015 , 977miles later I start getting a rough vibration at 60mph, then a "CHECK ENGINE LIGHT" ,guess the code - P0300 , pop cap off again and guess what's missing, YEP ! the center tab on the rotor and it would still start and run. Supplier DID FURNISH a new rotor from a different brand. Can I get any wagers on it, think I will still keep my used spare handy. Just hope it ain't 20 degrees next time. Thanks for your video , I didn't know about the ventilation in the cap . Noel

[@GoTechTraining]

+Kieffer Brothers That's odd that you're having multiples break off. What's the condition of your plugs/wires. Maybe you have too much secondary resistance and It's causing excessive current to travel through that rotor. That's where I would look at this point. Let me know what happens. Mike Becker, Technical Services Instructor

[@E9859-v7d]

Informative and classy . Your time is much appreciated. Thank you.

[@egadgetguy]

My P0300 and rough idle/run on my 2004 lesabre turned out to be the Ignition Control Module. $135... Autozone tested it and it failed, i replaced it and the car runs great now.

[@GoTechTraining]

+Ken Williams That's great Ken, glad you were able to get it fixed up! Mike Becker, Technical Services Instructor

[@GoTechTraining]

What a great question! In fact I am just moving into a new shop and am planning to look for a light. I will be searching for a corded light. I have not seen a rechargeable I really like. I will let you know what light I choose. Mark Hicks Wells Vehicle Electronics

[@herbwhitmore4482]

The best explanation I've found ..very good

[@GoTechTraining]

Thank you very much Herb!!! Mike Becker, Senior Instructor

[@JohnnyBGold]

great video . fantastic how they do the a zoom in on the parts and get they inside look on what's going on those parts and the functionality. thank you thumbs up and subscribed

[@GoTechTraining]

+JohnnyBGold Thanks JohnnyBGold! We appreciate it! Glad you enjoyed it. It is nice being able to see the parts up close, it does really help explain what and how things go bad! Thanks for subscribing. If you head over to our website you can subscribe there and get emailed reminders every time we have a new live training class! www.wellsve.com/webcasts.html Mike Becker, Technical Services Instructor

[@GoTechTraining]

Cleaning the cap and rotor may not be enough, you might have to replace them. Be sure to also check the ignition wires. The next step is to consider the fuel system. It is common for the fuel pressure regulator to fail on your vehicle. Mark Hicks Wells Vehicle Electronics

[@danthomson1182]

Came here for help, stayed for the editing. Haha wicked video guys.

[@adamcorria1647]

My god I love the video helped with both my 1996 and 1999 that was kicking my but with a misfire issue that I couldn't get rid of tell I pulled the screens out . thank you.

[@GoTechTraining]

Hey Adam, glad you enjoyed the video! Mike Becker, Senior Technical Instructor

[@GoTechTraining]

Thank you Brandon means a lot to me! Mark Hicks Wells Vehicle Electronics

[@jamesvanhoose3132]

This is a very well made video. Thank you.

[@GoTechTraining]

Thanks James! Mike Becker, Senior Technical Instructor

[@mariohernandez-qq9ed]

Well made and presented! Good job guys!

[@StevenC1956]

Thank you for your overview of the starting possibilities. You are good at explinations

[@GoTechTraining]

Thank you for the kind words. They mean a lot to us! Take Care and Happy New Year, Mark Hicks Wells Vehicle Electronics

[@felplayvina]

Thank for the video Mark, and very good explanation ending po300 could be ignition, fuel or mechanical issue. I will keep it in my mind.

[@639Beaver]

Great video. Enjoyed hearing great info. Will continue to monitor your videos, Thank you very much.

[@brandon3308]

Recently subscribed and I'm really enjoying your videos. I like your video editing

[@giantAsFan]

Great video I have a 95 tacoma with similar issues2.4 ,the truck slight miss at idle Aldo at low speed acceleration feels sluggish & hesitant,,,no ce code or light on , I cleaned maf, new plugs, cleaned throttle body,o2sensors cleaned, air filter cleaned ,brand new plugs I cleaned the rotor / dist cap & still runs sluggish please help

[@mattpoffenbarger]

Wow fantastic video so well-versed in explained thank you

[@GoTechTraining]

Thanks for watching Matt! Mike Becker, Senior Instructor

[@roylwchez]

my problem is the 98 s10 stumbles under load. p300 was cleared and hasnt returned. it idles a little rough. runs fine otherwise. just when climbing small hills i can feel it bucking any help would be greatly apperciated. I have changed the coil cap rotor plugs and wires next will be the distirbutor since the cost 100$

[@TheRaularya]

👏 👍👍 well done video love the green screen in the back you guys are awesome now I see what’s going on

[@the2120company]

fantastic video 👍👌 . the way you guys made it its like starwars i love it.

[@GoTechTraining]

Star Wars is next :) Thank you! Take Care My Friend, Mark

[@ahill007ny]

NICE!!!!!!!!!! MISSED YOU!!!

[@mparsons275]

Check the Electronic Spark Module under the coil packs, fixed mine!

[@81zed]

Here's my problem. I have a 2005 GMC Safari with the Vortec 4.3. I too have a P0300 misfire code and have been chasing it for a while now. Here's what I've done. I have replaced the spark plugs, cap, rotor, fuel filter, downstream O2 sensor (shot) and still have P0300 code. I have also replaced the distributor as well. All GM AC/Delco Delphi parts were used and bought new. I have also tested the fuel pressure as well and it seems to be within spec. Overall it runs very smooth and my fuel economy has not been affected (17 city, 24 hwy). It runs pretty good on the highway between 60 and 70 mph but when I go faster than that (75-80) it begins to run rough and the SES light blinks. It also happens when going up a long steep grade as well. Power drops, engine roughness occurs, and a smell (fuel??). I'm thinking MAF sensor but it's not throwing a P0101 code. Any thoughts Mike??

[@GoTechTraining]

Going off of your description it sounds like a possible fueling issue, such as bad injectors or something like that. Fuel injector issues are common on the 4.3L. When you shut off the key with a fuel pressure gauge installed do you lose pressure or does it maintain pressure? Mike Becker, Technical Services Instructor

[@81zed]

When I shut off the key with a fuel pressure gauge attached, pressure seems to hold. I've thought about the fuel pressure regulator but in my experience with other vehicles, it's pretty obvious with all the black smoke, etc., but I could be mistaken. I'll double check it again to be sure. BTW, I cleaned the MAF this morning and the problem is still there. Coil maybe?? I just wish the damn thing would blow up...then I'd know! Lol. Thanks for your reply Mike!

[@GoTechTraining]

What kind of pressure are you reading on the gauge? Maybe it's low? It could be a coil too. That's a cheap fix compared to replacing the fuel injector assembly or the fuel pump. Mike Becker, Technical Services Instructor

[@basslinin]

81zed If you can smell fuel then the engine isn't burning enough fuel i.e. running rich and the air to fuel ratio is off...i would look imto the exhaust side as well

[@GlynRobinson]

I'm getting a P0300 code when driving over 2000 RPM. Engine runs great tho. Replaced so many parts, including distributor and crank sensor. I think the ignition advance is not right.

[@GoTechTraining]

Hey Glyn, what kind of vehicle? Mike Becker, Senior Technical Instructor

[@GlynRobinson]

2003 S10 4.3L automatic

[@GoTechTraining]

Glyn, what about fuel pressure? Mike Becker, Senior Technical Instructor

[@jorgitocobain5253]

ya le cambie el alternador y sigue la misma falla ahora lo ke note eske en boton ke activa el desempañador se calienta mucho y empiesa a bajar el voltaje hasya 12.6 esto puede durar 5 munutos a 10 maximo en lo ke baja de ahi se apaga x completo el tablero y aparece una leyenda ke dice hot AC disabled y se apaga el carro crees ke tenga ke ver algo con el aire acondicionado saludos...

[@CrashWanderer]

I got the same code as well. But it only comes on when I push my 2000 Chevy Blazer upwards of 75mph (and seems like it jerks very slightly) and after a few more starts the check engine light turns off. Do you have any idea of what it might be? Idk if it has anything to do with it but it does have trouble starting every now and then. And even with the light flashing, it seems to hold power, but also seems like it runs slightly more at a higher rpm (when it flashes).

[@GoTechTraining]

There are a ton of reasons a P0300 is setting on your vehicle, but here is a good place to start looking. 1. Place a dollar bill against the tailpipe during the misfire, rough running. If the dollar bill pulses back INSIDE the tailpipe, there is a mechanical problem with the valve train. Use a top engine cleaner to soak carbon off the valves, retest. 2. Check for good spark output at the end of the spark plug wires. 3. Check for a bad distributor cap and rotor. 4. With the engine running, wiggle the White wire and the White/Black wire at the ignition module. If the engine bucks and jerks, repair the wiring. Stay in touch, Mark Hicks Wells Vehicle Electronics

[@GoTechTraining]

Siento que estoy teniendo dificultades para comprender. Si he entendido bien, el aire acondicionado no está activando. La primera cosa a comprobar es asegurarse de que el refrigerante está llena. Mark Hicks Wells Vehicle Electronics

[@hondaatc1987]

I have a PO300 and a PO304 CYLINDER misfire on cylinder 4. I replaced rotor cap wires plugs and cleared code then it comes back same side again.misfire 4.. could it be the fuel injectors?

[@GoTechTraining]

Steven, it could be an injector. Could be a compression issue or a breathing issue as well. Did you check compression on that cylinder? Mike Becker, Senior Technical Services Instructor

[@hondaatc1987]

Wells Vehicle Electronics I found the Problem, it was a clogged/bad injector on #4 cylinder. I installed a new set of Spider Injectors and it runs perfect!

[@KC-vp7wn]

So I replaced the cap, rotor wires and plugs back in August. The car ran fine rain-or shine. It’s January and 40 degrees out and 99% humidity out. When the car idles I get no missing but when I give it gas the engine misses. It all goes away when the engine is up to normal temperature. I’m wondering if the high humidity and the possibility of the screens clogged is the problem. So strange as this was the first time I’ve changed the cap an rotor sense 2010 and never ever had any problems with the engine missing! I just figured that it was long enough and I change it because of the age. Frustrated

[@Dannyaudio69]

Do you test the spark with car on or off?

[@oldredcoonhound2182]

I was getting p300 random misfire for two years. Two GM shops couldn't figure it out. I got pissed off, changed all plugs, wires , coils, fuel filter. continued with code. then last summer I started getting p1516. changed my throttle body. took to a different dealer and their mechanic poured water on the intake manifold. and found that the intake gasket was causing the p300 random misfire. I now get 15-16 miles per gallon instead of 10 now

[@GoTechTraining]

+oldredcoonhound P0300 can be very tricky to find, glad you were able to get to the bottom of this one! Intake gaskets are tricky to find. I prefer using brake or carb clean to check for a leak, rather than water. Also sometimes intake gaskets only leak on a cold engine and seal back up when the engine is warm, making them even more fun to find. Mike Becker, Technical Services Instructor

[@dmorley100]

Was startin to wonder if you were ever gonna upload any more videos :)

[@Snowman3g]

Great video You just got yourself a new subscriber. I hope this is the problem with my bravada. I have a 97 bravada with 212k I love it even though it has a few problems . It wasn’t misfiring but I knew it needed the plugs and wires to be changed. So I got the denso iridium plugs and some new wires and the distributor cap but now it runs very bad and shakes smells like gas and it pops even at idle also the alternator get very hot. One of the screw holes from the distributor broke when I was tighten the cap so I just zip tied it down can that cause the problem? I didn’t want to drive it but I had to take it to autozone so the can scan it and the main problem was po300. When I drove it smelled like something was burning gas or plastic or something. I gapped all the plugs at .60 and put the wires in order. I don’t know what to do can you please help thanks.

[@GoTechTraining]

Hey, thanks for watching! A P0300 is a random cylinder misfire. I don't really see how zip tying the cap tight could cause that. As long as it's 100% solid...best case would having it bolted down. If that caps able to move it could cause your issue. Mike Becker, Senior Technical Instructor

[@houstonhotdog5273]

I have 97 s10 p0300 changed sparkplugs, wires, dist cap and rotor still has p0300 starts and runs but not running right and backfiring plz help

[@chuckgoedicke7547]

verrrrrry informative thank your very much for the very useful info

[@GoTechTraining]

+chuck goedicke Thanks for watching Chuck! Mike Becker, Technical Services Instructor

[@tomandcarolejansen5507]

Your videos are all that is good!! You got me subscribed!

[@GoTechTraining]

Thanks Tom, glad to have you here!! Mike Becker, Technical Services Instructor

[@brt-jn7kg]

Okay what if you have a missed only driving but it doesn't miss at idle and you have no codes throne by the computer at all

[@GoTechTraining]

I would take a good look at secondary ignition. Worn plugs could definitely cause a loaded misfire. Mike Becker, Senior Technical Instructor

[@brt-jn7kg]

@@GoTechTraining I know you're crazy busy. I should have given you some more information to go on. 1996 Chevy c 2500 5.7 l bortek rear-wheel-drive NV 4500 Standard transmission. Mopeds crack even load the truck never ever got hot. This is happened after both heads will replaced. New plugs brand new distributor cap and rotor new wires. It's crazy. New fuel regulator and pump was replaced about two years ago. It's not ever thrown a code. Cleaned and inspected the mass air sensor and cleaned the throttle body. Checked the EGR against the proper book checked to be working properly. I checked every vacuum port and line with a propane unlit torch and intake gaskets. I think that's it. I'm far from a master mechanic but I grew up turning a wrench and I have a small business working on Evinrude Johnson outboards. Thank you in advance for your time!!!

[@styme930]

* Bows down to mark * for I have come across a guru and I shall not let you go without a fight

[@GoTechTraining]

LOL I will be here to help when ever I can! Remember to let me know how the test turns out. Take Care my friend, Mark

[@derekwu3256]

Just replaced all coils/spark plug wires and spark plugs in my 2015 Chevy 2500 6.0 Still getting p0300.. comes up randomly and when it does it idles really rough and tried taking it for a test drive and see the power decrease

[@GoTechTraining]

How are the fuel trims? Mike Becker, Senior Technical Instructor

[@derekwu3256]

NGK Technical Training it looks good Chasing this p0300 is such a pain

[@tpcoachfix]

Excellent video

[@ShanerTheGrey]

Great video!

[@GoTechTraining]

Thanks Shane! Mike Becker, Technical Services Instructor

[@cynicaltexan9639]

My #3 cylinder is misfiring. replaced spark plug seemed to fix it, the code stayed away for about a day than came back going to try the coil next. (3.6L pentastar)

[@GoTechTraining]

Hey, be careful swapping out parts like that. A single component can take out other components and you could end up in a never ending cycle. A bad plug can take out a coil. A bad coil can take out a plug. Mike Becker, Senior Instructor

[@cynicaltexan9639]

@@GoTechTraining I just order the parts to replace all coils and plugs.

[@foreverstrong693]

Great video!😎🤙

[@tonydeighton7455]

I'm having the p0300 fault plus p0171, p0131, p0137. I have replaced the the fuel pump, fuel filter, pressure relief regulator, plugs, wires, cap and rotor and still getting these faults recurring. Not sure what else to do now.

[@GoTechTraining]

Tony, sounds like a complex problem. Let's start with what kind of car you're working on. Year, make, model, and engine. Mike Becker, Technical Services Instructor

[@hddm3]

what work light would you recommend? rechargeable thanks

[@Lincolnls00arturo]

Osome video. Kip them coming. Tank you guys for the help.

[@GoTechTraining]

lincolnlz00arturo Thank you for the great comment and kind words. Means a lot to us at Wells. Should check out our live training sessions on hangouts. Mark Hicks Wells Vehicle Electronics

[@JustJoshin27]

Where can I find a good tech in Maryland? I've yet to get any good service in Maryland.

[@GoTechTraining]

Finding a good tech can sometimes be a real challenge. Below is a link to an ASE site that might help you. www.ase.com/landing-pages/car-owners/find-a-repair-shop.aspx Take Care, Mark Hicks Wells Vehicle Electronics

[@Kaibil66]

Great video

[@GoTechTraining]

Thanks Kaibil66! Mike Becker, Senior Technical Instructor

[@lssu86]

Crank relearn fixed my PO300 on my 6.0 Silverado. Took less than 5 min with a scan tool.

[@GoTechTraining]

Thanks for the great tip! You are absolutely correct! If your vehicle sets a P0300 code, but you do not feel a misfire performing the crank relearn might take care of setting the code. However, if there is an actual misfire occurring and the crank relearn is performed the check engine light will again illuminate setting a code. When the crank relearn is performed it is telling the computer the signal it is receiving form the crank sensor is the correct one, even if it is a bad signal. When the misfire problem gets worse the code will again set. Take Care and thanks for the great comment! I am sure because of it you and I are going to help a lot of viewers better understand the system. Stay in Touch, Mark Hicks Wells Vehicle Electronics

[@george536]

thanks for the video, always like these

[@QQTrick1QQ]

Why would it throw a P0300 with a P0302 problem? I have a P0300 code with 1,6 and 8 high count misfire and can't nail it down, will try a relearn next.

[@GoTechTraining]

It sets a P0300 due to random misfire, so they say. It is really because the computer can not determine which cylinder is missing. Depending upon which vehicle you have, doing a relearn could cause the computer to think the misfire is correct running. Stay in touch, Mark Hicks Wells Vehicle Electronics

[@АлександрБондаренко-ы2к]

What diagnostic program do you use? How can I download this program?

[@GoTechTraining]

We mainly use Alldata and Identifix. You need to purchase them either monthly or yearly. Mike Becker, Senior Technical Instructor

[@danielmoore7983]

I have a 2005 GMC 2500 Savana Cutaway 6.0L. Can not find anyone in Vacaville or Fairfield Ca. That can repair vehicle with P0300 code. For the past year I have been back and forth with 2 Chevy dealers, We have replaced Crank Sensor, Cam sensor ,plugs wire's, harness, and last time dealer had it they said it was thrust washers on crank. Now it has a new motor and same code. It has traveled about 500 miles. What happened to the Mechanic. Only can find R&R people in this area. Any Idea's??

[@GoTechTraining]

Hey Daniel, sounds like you have one heck of a headache going on. Now a lot of times people overlook the simplest of things. I want to start you back at the beginning. First of all, is this truck flex fuel? 2nd of all, is the fuel in this thing ok, no water in the gas? 3rd...have you had a crankshaft relearn procedure done? That can set a false P0300, and still run just fine. Please let me know what you think. Mike Becker, Technical Services Instructor

[@jorgitocobain5253]

hola tengo un olsmobile royal 1994 en el tablero marca un voltaje de 13.5 en hasta 14.2 bajando de 13 el carro empiesa a fallar y se apaga me podrias desir ke falla puede tener te lo agradeceria saludos

[@thump1st]

Greetings! Got that code. Changed spark wires, coil pack, sensor, & still have the code and rough idle. Could it be fuel injectors?

[@GoTechTraining]

Anything to cause a misfire could cause the P0300 code. What is the year, make, model and engine size of your vehicle? I will look it up to see what is most probable to cause it. Mark Hicks Wells Vehicle Electronics

[@thump1st]

1996 Buick Century with a V6 3100

[@GoTechTraining]

First check the injector wiring harness behind the alternator for rub through. This is pretty common especially if the alternator has been replaced. The next most common cause is a defective injector. Hope this helps, stay in touch, Mark Hicks Wells Vehicle Electronics

[@thump1st]

Thanks so much. Youve always been helpful. Appreciate it

[@wardellb9737]

Hello, my check engine light came on while I was going to work, The check engine light was flashing so I put into a gas station, My engine got loud or the idle was very rough, I took my car back home which was like 7 minutes away, I had a code reader which said P0300, then I notice my catalytic converter was very red. I have a question, I am going to get converter replace today, Will that solved the P0300 issue? Will I have to replace both Oxygen Sensors. I have a 2005 chevy classic(malibu) 4 cylinder.

[@GoTechTraining]

+Wardell B Hi Wardell B, chances are the P0300 is caused by something other than the catalytic convertor and if you replace the cat and don't fix anything else it will likely fail again. It's hard to say if your oxygen sensors are ok or not. At this point you want to diagnose the P0300. Being that the idle was rough that is probably causing your cat to get red hot. I would diagnose whatever is causing the misfire before putting a new cat on, you could damage the new one. Mike Becker, Technical Services Instructor

[@wardellb9737]

+markjhicks I just found it out it was my Ignition Control Module, When my Ignition Coil got burn out in July 2015, the mechanic forgot to replace the Ignition Control Module, My dad and I check the spark plugs yesterday, they were new, the ignition coil and the boots were good, then we noticed the Ignition Control Module was burned. The check engine light is still but not flashing now. I have to new get a new catalytic converter and o2 sensors. Hopefully the check engine light will go off tomorrow

[@GoTechTraining]

+Wardell B Good to hear you got to the bottom of it. The light will stay on until everything is fixed and the car passes its tests. The flashing light was on because the bad misfire was causing damage. Now that you replaced the ignition control module chances are you just have a bad cat/02 sensor(s). Let me know how it goes after the cat is fixed. Mike Becker, Technical Services Instructor

[@wardellb9737]

Hello Mark. I had my cat converter change, My dad change the downstream O2 sensors, the check engine came on, then it went off. Two days ago the engine line came on, so I went to Auto zone, the code reader said it was the code P0420, does this mean the upstream O2 sensors need to be change? I order the upstream O2 sensor this week along with the Purge Valve Cansiter. I have another question, my dad and I change the engine mount and 3 trans mounts on my car, The mounts were very bad, Today I was at the stop light my car was vibrating in the drive gear and reverse gear, but in the neutral gear, it was quiet for a while then it went back vibrating. Could this be the rotors or its time for me to get the transmission oil flush, I never had my transmission flush or the filter replace. My car is over 127,000 miles, its a 2005 chevy classic.

[@GoTechTraining]

+Wardell B The p0420 is a catalytic converter low efficiency code. It doesn't mean that the 02 sensor is bad but it is a possibility. Did you install a high quality cat? As for the vibration it's tough to say what could be causing that. Does it only happen when you're stopped? Mike Becker, Technical Services Instructor

[@GoTechTraining]

Compruebe el alternador. Mark Hicks Wells Vehicle Electronics

[@moddmodd88]

Great video !!!

[@GoTechTraining]

syed ali Thank you for the kind words, they mean a lot to us!Mark HicksWells Vehicle Electronics

[@jerrymarshall2095]

Very good

[@GoTechTraining]

Thanks Jerry! Mike Becker, Senior Technical Instructor

[@tarahbl7521]

i have a random misfire and loss communication with ecm pcm

[@GoTechTraining]

Alright, what kind of vehicle? MIke Becker, Technical Services Instructor

[@Nudnik1]

use OEM caps....alot of issues with after market parts.

[@GoTechTraining]

Sure, some aftermarket caps have problems...Ours are built to be OEM equivalent! Mike Becker, Senior Technical Instructor

[@Nudnik1]

NGK Technical Training Except NGK.

[@UsoFamily253]

thank you for the video now i know how to fix my car.

[@GoTechTraining]

You are welcome! Your kind words mean a lot to us! Take Care, Mark Hicks Wells Vehicle Electronics

[@styme930]

I must ask you markjhicks you seem really intelligent when it comes to a vehicle , I do not have any codes I have not yet purchased a GS500 OBD2 II Scanner Tool but I shall soon , my trouble is a getting up and moving , it seems like the fuel pump is my major issue , I have spent money to have a new jasper engine put into my 2000 chevy s-10 I also spent the money for new spark plugs as well as ignition wires , just when I need to pull into traffic it hesitates sometimes it wants to move and a great deal of time I can push it faster to get it to move , can you please help me ?

[@GoTechTraining]

I am happy to help you. First i need a couple things. What size engine is in your S10? From what you said, it sounds like it hesitating when you accelerate from a stop. When this happens, does the engine rev up and you don't move or does the engine die down and then catch? Mark Hicks Wells Vehicle Electronics

[@styme930]

markjhicks Vortec V6 4.3 I need to post an image to this site but can't , I was told , the air intake ( not sure of the name of part needs cleaned or replaced , it comes after the air filter and in between the wide hose ( small metal part with arrow between the two clamps . Yes it revs up and will not move , turtles can run faster but it drags so slowly , I have pulled out a few times into traffic I am so grateful they applied their brakes .

[@GoTechTraining]

The part you are referring is the Mass Air Flow (MAF) Sensor. However, if the engine revs up but the vehicle does not move, the problem is not the MAF sensor. It means there is an issue with the automatic transmission or clutch (Standard Trans). The problem is not the engine. If you have an automatic, pull the dipstick and see and smell the fluid, if it is burned chances are you need the transmission rebuilt. Mark Hicks Wells Vehicle Electronics

[@styme930]

markjhicks Can't be the transition Aamco Boardman Transmissions is a company I trust and when Rick bates garage was told by the supervisor at Aamco his transmission ( yes mine ) is something he himself would love to own and have , I hate to stump you but my transmission passed all test's I put Aamco threw , they cleaned it out , replaced filter and even smiled for the work I made them put it threw , even today my fluid is still a red color , not filthy at all . Sorry to confuse you .

[@GoTechTraining]

OK, please let me clearly understand what you are saying. When you step on the accelerator from a stop the engine goes faster but you do not move or you move very slowly. Is this correct? Mark Hicks Wells Vehicle Electronics

[@einarthoroddsenskulason1115]

I have a 2006 Kia Rio. I just cleaned the throttle body and when I start the car it can´t keep it self running in idle. Also it runs poorly driving steady. The check engine light did not come on but I got the p0300 code. Just wondering if anyone has any advise ??

[@GoTechTraining]

Einar Thoroddsen Skúlason Try removing the ECM fuse for more than 10 seconds. This will clear the adaptive fuel trim values. The most common cause for the P0300 is defective coils on your vehicle. Start by checking the spark plugs. If they look bad, I would replace them and the coils. Stay in touch, Mark

[@einarthoroddsenskulason1115]

markjhicks I checked the sparkplugs and coils. The plugs on cyl. 3 and 4 are very rusted but I checked the sparks and they are steady so plugs and coils are good. I´ll try removing the fuse next. Also I already disconnected the battery for about 30 min, cleaned the egr valve and reconnected the battery. I´m thinking, could it be the TP sensor or a O2 sensor ?? If so, the check engine light should be lit, right ??

[@GoTechTraining]

Einar Thoroddsen Skúlason It would be very unlikely the TPS or O2 could be causing these issues. Granted the O2 may have been destroyed but it is not the cause. The method you used to check the plugs and coils is honorable but I think the results are skewed. When a plug is under compression it is much more difficult to bridge the gap than when it is in the open air. How many miles are on the engine? To check the coils more accurately use a gaped spark tester. One you can set the gap with. Then try the coils during cranking and I think you might see them break down. Mark

[@Dookie_burner]

4.3's have a huge distributor

[@mobilesportmobileempirecus9136]

Nice work on the video. Subscibed

[@GoTechTraining]

Thanks! Glad you enjoyed it. Mike Becker, Technical Services Instructor

[@hddm3]

thank you

[@carslover3509]

great

[@GoTechTraining]

Thank you for subbing, greatly appreciated! Mark Hicks Wells Vehicle Electronics

[@sarahbelanger1746]

acurate but in the real world you have to take into account mileage, age of vehicle, and state of maint. this engine has the dubious tendency to develop vacuum leaks around manifold. this can damage and create other codes over time.

[@GoTechTraining]

+sarah belanger Sarah, you are right and thank you for bringing attention to another reason the P0300 code may have set. Yes, mileage and maintenance are huge factors contributing to the vacuum leak issue. I want assure you every one of our videos and training events are from real world failures. Nothing we do is set up or proped. On this particular vehicle we did not need to go any further, the cap, rotor and ignition wires took care of the misfire. Thanks for your comment, we appreciate you, Mark Hicks Wells Vehicle Electronics

[@daviano]

Brining my infiniti to the auction because I can't finger out what giving my own that problem

[@hugomejia1562]

Tengo el code P0300 trail blaser 2002 4.2l

[@GoTechTraining]

Saludos Hugo con respect a el codigo P300 es un codigo que representa fallas multiple de varios cilindros. Lo que yo revisaria seria las bujias pero primero revisaria si el motor tiene una fuga de vacio, tambien revisa todas las mangueras del motor para estar seguro que no esten jalando vacio. Si todo esta bien bueno revisa las bujias. Si tienes uso de un escaner revisa el motro cuando esta fallando para ver que cilindro esta fallando bajo potencia. Este es mi correo por si necesitas mas ayuda ok. [e-mail] espero tu repuesta Fritz Fuchs Instructor de Servicio Tecnico Automotriz.

[@TheTravellingHobo]

Fucking great video

[@trainer2018]

Nice video Mr. Hicks, I have a subscription recommendation for you, Daniel Sullivan's electrical diagnostics channel. Check it out.