GMC and Chevy 5.3L Trucks P0300 Random Misfire and Sometimes No Spark

[@spelunkerd]

Love the way you walk through the diagnostic steps, a flowing logical thought sequence.

[@anthony-r2b]

Hi just wanted to thank you I had the same problem with my 2007 chevy Silverado 5.3 same code p0300 did everything thing I could to fix it nothing worked I was ready to have it towed to a mechanic but I looked at video did what you did you said and it was the ground wire fix it and my truck ran perfect, can't thank you enough for your video 😅😅😅

[@Virgo0870]

excellent video best one I have seen so far on this particular problem I have subscribed to your channel and will tell my friends about your channel also thank you sir

[@roberthanna4400]

Brother I really appreciate this video! I just did a DOD delete on my buddies Yukon got it all put back together and it had no spark and instantly I went into panic mode thinking I had the timing set wrong! I thought I was going to have to open the motor back up!! But after stumbling across this video I checked the same ground and it was broke did a little quick repair and it fired up first time! Once again thanks for the video you saved my butt thanks!

[@mostafaelhosseny2600]

@@roberthanna4400 I have a cylinder 3 misfire, I changed the spark plugs,coil,wire and still the same issue Sometimes a misfire is coming and going while driving then the vehicle is running smoothly, NO lifters noise at all , My mechanic said it's probably a lifter or Valve lifter oil manifold (VLOM) It's 2014 GMC SIERRA 5.3

[@tpm3092]

You're awesome! Had the same problem with the driver's side bank not sparking on my 4.8L Silverado (07 New Style). My grounds looked fine to the naked eye, not broken like the one in the video. I put a new connector on and problem solved, firing on all 8 now. Thanks for another great lesson

[@TheGAutomotiveAndMore]

This one was broken inside the connector but that green corrosion will cause the same problem. Thanks for watching

[@Kruznlow69]

Thanks for making this video. Was so frustrated after degreasing the underside to pull oil pan for an oil leak (AWD Denali) and all back together and ran like crap. Musta broke last bit of connection when scrubbing. Crimped and soldered new connectors on and BOOM, ran fine no codes. Thanks!!!

[@MikeD-ey3sx]

Saved me hours of tech time!. I hate electrical and your video saved me from getting sick from grueling b.s. diagnostic time. Thanks man!!!!!!!.

[@feeldhertz]

Awesome help bro, you are truly a hero. For the past month I have been having issues with my truck, three different shops changed out spark plugs twice, coils, plug wires, MAF, throttle body, cam sensors, air filter... $4k later and truck still ran like crap with one bank refusing to work. This morning I tried this and whaddya know it solved my rough idle and acceleration problem engine feels like full power. Only issue I have now is it overturns a bit before startup but I think it might be the purge valve will replace it tomorrow.. Thanks a lot, is you're ever in SFla I got some brewskies with your name on it 👌👍

[@TheGAutomotiveAndMore]

Thank you and thanks for watching

[@finessinbandz9703]

Pll

[@93shortbedchevy]

​@@TheGAutomotiveAndMoreI have a 2007 GMC Yukon Denali I have the same problem I did a temporary fix and it has worked for about six months can you help me out and point me in the right direction to where my ground wire is please and thank you this video was 100% helpful and I'm definitely following you after watching it

[@Virgo0870]

You sir are a excellent mechanic I never knew those grounds were there I got a p0300 code while driving on the freeway and I got a lean code and I was thinking that I had a bad coil or coils, or maybe a bad injector after I watched your excellent video I was able to locate the grounds and they had corrosion on them I cleaned them up with some 600 grit sandpaper and now my 2007 Yukon has power when I step on the gas and is running a lot smoother thank you

[@TheGAutomotiveAndMore]

You welcome. Just remember the the wire can corrode in the eyelet. I would replace the eyelet. Thanks for watching

[@jfeal]

Guess what I'll be checking this weekend! Thank man!

[@sea69man]

Thanks, good job. Nice, simple and something to look at because sometimes it is the simple things that you miss and scare us about "what else" is going wrong with all the electronics. Taking it to the garage now you need to mortgage your house. Thanks so much.

[@billsmith2212]

That factory crimp had exposed copper from day 1 . Add water and road salt and green crusty = high resistance on the ground side . I wonder if you did a voltage drop test from the tab in the end of the wire to the center of the post on battery negative if would show up while running or cranking it . It has got to have current flowing to test . I would seal any exposed copper to prevent a return . Nice find .

[@112785jam]

I just saw this video, my whole driver side bank isn't working I was getting ready to buy the 4 coils, I'm hoping this is the issue. Thanks for the vid

[@TheGAutomotiveAndMore]

I hope so too

[@PeterRichardsandYoureNot]

“Comes out easy, goes in hard!” That’s what she said...sorry, couldn’t resist. Thanks for info, should be relevant in my Chevy.

[@TheGAutomotiveAndMore]

I will just leave that alone. Thank for watching

[@walterkersting1362]

Wrong hole...

[@TubeAirways]

😂 😂 Same thought

[@Foghorn77]

This video solved my dead passenger bank issue on my 6.0. The connector itself looked fine but once cut out and tested with a meter it had no continuity. Thank you so much.

[@TheGAutomotiveAndMore]

I sill can't figure out why the ground for the coils is all the way down there. Thanks for watching

[@Foghorn77]

@@TheGAutomotiveAndMore A ground block with all the grounds lead to it would be so much better.

[@EnduroRacer18]

Thank you! Found the gnd was gone on the even bank. I would have been introducing a new gnd if not for your video showing where it gnds to the block. Nice!

[@TheGAutomotiveAndMore]

Thanks for watching

[@patmitskey839]

An OUTSTANDING, diagnostic video Partner 👍👌😎

[@joeturtleneck2300]

oh man, you're a life saver, i hope this is my issue

[@yeaboi5377]

Well was it

[@alexcalderon5158]

Was it?

[@cody3549]

Was it?

[@PDGaming]

Was it?

[@SemperShock]

Was it?

[@BrianMoffett]

Absolute life saver, thank you.

[@fazomontana2807]

I wanna be you when I grow up that fixed my issues

[@jacksmith3189]

Good information I have an LQ4 and will keep this in mind Thanks

[@TheGAutomotiveAndMore]

Ground wire should be in same place. Thanks for watching

[@edwardthayer9386]

Great video and attitude!👑🏆

[@Virgo0870]

You saved me a lot of money thank you

[@mostafaelhosseny2600]

I have a cylinder 3 misfire, I changed the spark plugs,coil,wire and still the same issue Sometimes a misfire is coming and going while driving then the vehicle is running smoothly, NO lifters noise at all , My mechanic said it's probably a lifter or Valve lifter oil manifold (VLOM) It's 2014 GMC SIERRA 5.3

[@mostafaelhosseny2600]

Any idea what's going on 😅

[@reelmilitia6975]

Fingers crossed this is my issue!! I went over some train tracks and then truck felt like it lost half power, flashing engine light. Went to check spark plug wires when I got home and they just broke so I went to replace plugs and cable and the whole driver side bank all the plugs are fouled out bad and the passenger side looked perfect. U1000 and P0300 codes. Will be replacing these connectors once I get home and update!

[@michaelmajor5467]

It's been 3 months what's the update was it the wires?

[@reelmilitia6975]

Michael Major ... no fix, it’s at the 5th mechanic. No one can find the problem, still only code is for random misfire. It’s some how getting extra fuel into cats. I changed cats, computer, plugs, wires, o2 sensors, map, oil pressure sensor, all grounds, smoke test, removed timing chain cover verified no jump, compression good on all cylinders. I’m at a loss, this is crazy!!

[@jahlieel.e7856]

@@reelmilitia6975 did you check your coils. Take them out for cracks if they shift when push/pull on them. And check injectors connector plug, for brakes.

[@miguelortega2836]

@@reelmilitia6975 Did you check the Mass air flow sensor?

[@reelmilitia6975]

@@miguelortega2836 Yes, replaced MAF and MAP

[@jahlieel.e7856]

Im having the same problem on my 03 suburban, change plugs ,wires, coil#1 that was cracked, runs good for a bit. 10min later flashes check engine light. I'll look into them ground in the morning.. stay tuned.

[@denisbartolotta7517]

Please let me know I have same story replaced coil cables and spark plugs still same issue

[@asaphlane1089]

Good work man 👍🏾

[@laymanware7350]

Awesome video 👍

[@craigquann]

I'm having the same problem. Just put new plugs and wires (the old plugs only had 30000kms). I did check the grounds and sanded them. But perhaps I should get a closer look at them.

[@TheGAutomotiveAndMore]

They could be green with corrosion and broken like in the the video. Thanks for watching

[@craigquann]

@TheGAutomotiveAndMore yea, I'm going to have to take a closer look. Mine is very intermittent. Like one or 2 events every few days to a week with no rhythm or reason. Since I only did a quick clean from up top, it didn't really give a great view.

[@93shortbedchevy]

Thank you for this video i have a 2007 gmc yukon Denali and im having the same problem i temporary fixed it by splicing in a ground but now its doing it again can you point me in the right direction to fix it the right way please

[@TheGAutomotiveAndMore]

I think that's is in the video.

[@stevenosgood3890]

Thanks 😊 Boston Ma.

[@weird4452]

Found the ground location but wow it seems impossible to get too. Even to change the connector hardly enough slack on the wire to replace it. Im guessing I’ll have to try and disconnect a bunch of the harness to try and bring it out more??

[@TheGAutomotiveAndMore]

Yes Its tight up there

[@MrAyala011]

Thank you so much man, i just fix my 2007 GMC Sierra same issues thats all it was.

[@TheGAutomotiveAndMore]

Great, thank for watching

[@KTHKUHNKK]

@@TheGAutomotiveAndMore Holy Crap These Vehicles today will keep us broke.

[@vincentrodriguez4395]

I replaced coil packs, spark plugs, wires too them, fuel injectors and starter. Still had a misfire. I checked it said p0300 but i did that live data and it says 4 and it misfires count just goes up!

[@KTHKUHNKK]

@@vincentrodriguez4395 OMG WTF these darn vehicles or something else. Computer this computer that Oh boy What a bunch of crap

[@TheGAutomotiveAndMore]

@@vincentrodriguez4395 Do a compression test to be sure that is ok.

[@yamaguy9846]

In my case, I swapped plug? Wire and coil but misfire remains on the same cylinder, any idea if its ground?

[@TheGAutomotiveAndMore]

Could be. did you check for spark coming out of the wire? If you have spark do a compression test.

[@eddiewilliams-pw3pr]

What does the other wire go to?.. mine sparks when i ground it...

[@TheGAutomotiveAndMore]

Both coil grounds go there but I do not know about the other wires

[@balball2000f]

Great info

[@DavidMartinez-r4r]

Was the truck stuttering prior to fixing the issue?

[@TheGAutomotiveAndMore]

Yes running bad and miss fire codes

[@unitewewill]

nice video thanks.

[@allanpomerantz83]

G automotive where are you located

[@TheGAutomotiveAndMore]

Northern Virginia

[@OfficerThumbs]

Can a bad fuel pump/ filter cause this also?

[@TheGAutomotiveAndMore]

That will not cause a no spark. But It could cause a random misfire.

[@fambam1666]

Honest machanic. Hard to find now day’s

[@TheGAutomotiveAndMore]

Thank you and thanks for watching

[@fambam1666]

@@TheGAutomotiveAndMore most of the honest ones are not here in california

[@banshee100]

i have a 02 gmc z71 10k miles on motor compression 150 150 160 160 160 160 160 160 brand new 8 injectors plugs coil wires brand new intake manifold brand new ac delco knock sensors brand new cats and fuel filter brand new fuel pump and regulator motor passes leak down WARRANTY company just replaced heads thinking that was issue still have po300 only missfires on 1 and 6 i have tried new crank sensor and relearn no fix what gives ?

[@TheGAutomotiveAndMore]

I would move the coils around and see it the miss follow where you moved the coils.

[@banshee100]

@@TheGAutomotiveAndMore it dont i have tried 24 diff coils 8 gm 8 oriallys

[@TheGAutomotiveAndMore]

@@banshee100 Ok then I would get a in line spark tester. Put it in line and see if you are losing spark.

[@SamarioDennis23]

Mines saying Bank 1 & 2... Mannn I hope this is my issue also I've changed everything 🤦🏾‍♂️

[@samchisolm5832]

Would this apply to the 2010 Yukon xl?

[@TheGAutomotiveAndMore]

Yes it should have the same V8 in it. Thanks for watching

[@Erik-nv6vu]

I got the same issue 2011 yukon runs fine but random misfire on 7 and 8, but it happen when I was hooking up a amp and check engine light been on since HELP

[@TheGAutomotiveAndMore]

I do not know. Try disconnecting the amp and see if that helps.

[@KTHKUHNKK]

Good Job

[@KTHKUHNKK]

I'm pulling a 300 code I have already replaced the fuel filter. I'm going to replace the fuel pump next. I'm also getting a 171 174 and po300 code

[@tpm3092]

Thanks!

[@TheGAutomotiveAndMore]

Thanks for the thanks. Thanks for watching 😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀😀

[@cornelius7812]

I have a 2004 GMC Yukon XL and I’m having the same problem slow acceleration and missing every one in a while I’ve had it at 10 different mechanic any assistance

[@TheGAutomotiveAndMore]

Check and replace this ground even though it might look good. This on had green corrosion in it. That could be causing your problem.

[@cornelius7812]

I’ve tried it still same problem it gets really bad at times when I go up a slight hill and transmission shift crazy at times not for sure if that has anything to do with it

[@TheGAutomotiveAndMore]

@@cornelius7812 Not sure it could be anything

[@j.d.7321]

It's still a shame these manufacturers are still using these cheap wire connectors

[@vincentrodriguez4395]

Can I just replace the whole wire? And I had trouble locating it. Is there any way you can show more?

[@TheGAutomotiveAndMore]

Yes you can but I would replace the other side also because both wires connect to the same point. It is most likely getting ready to break also. Thanks for watching

[@jeromegarcia5396]

I'm not sure exactly where you are but I'm sure I'll find it if I get under, the only problem in this was seeing exactly where, but I'm not a mechanic so probably just me...

[@TheGAutomotiveAndMore]

Its on the drivers side , front of the engine block

[@jeromegarcia5396]

@@TheGAutomotiveAndMore I have to take the plastic shroud under car off? I can't see or get to it from the top... I appreciate it, I'm hoping this fixes this problem. It's been getting worse, and is weird when the check engine light is on when you hit the gas it blinks when you let off it stops...

[@TheGAutomotiveAndMore]

@@jeromegarcia5396 Yes take the shield off

[@davidwest2773]

Nice

[@MechanicsAdvice]

I'll have to see if that's my issue, misfire only on drivers side 02 tahoe z71!!

[@joekillingsworth9002]

What if its not the ground wire ???

[@sinisterrevelations4493]

Wish i had of checked this a month ago seen this vid but thought it was only in 1 cylender. Replaced battery ,plugs, wires swapped packs, changed injector, replaced bank 2 upper and lower 02 sensorswith a code for upper then lower. Did compression test . Was getting a code 306 watched misfires was in just 6 then tested for spark because I thought others were working but same thing no spark in pass side bank and drivers side was just a orange blob not spark looked under took off yep same thing havent put it back together cause its night but sure it will do the job this misfire was so bad it smoked my caddy and bunt bank 2 upper and melted lower. This all happened when i was leaving a parts store for gas line for my boat .outta nowhere it happened limped it home. (UPDATE) battery dies was brand new crappy tire sucks but on the better note after almost chockin out the parts guy spent 5 hours charging the battery to full threw it in the truck and yep it was just the goround. Thanks man for posting this i thought it was in the dod system or somethin but this post saved me doe and time now i can do wood so i don't freeze this winter.👍

[@TheGAutomotiveAndMore]

That sucks, I hope this helps you. Thanks for watching

[@sinisterrevelations4493]

@@TheGAutomotiveAndMore Sure did man thanks saved me lots of doe and sanity 😂 I subscribed to keep up on fixes 👍

[@TheGAutomotiveAndMore]

@@sinisterrevelations4493 Glad it helped. Thanks for watching and subscribing

[@Aero_HER_Dynamic]

I have an 08 Chevy silverado 4.3L. Changed plugs and wires for P0300 and P0449 Evap solenoid is changed also. CEL back on and truck still runs ruff at idle or stop light. P0304 cylinder 4 misfire and P0300 multiple misfires.......i dont know what to do at this point....I dont have fuel injectors on the 4.3 from what ive heard.....Could it be a ground or if anything else please inform me!!!!!

[@TheGAutomotiveAndMore]

Make sure you are getting spark to number 4 cylinder. If you do, then do a compression test on that cylinder. If that is ok then it could be a fuel problem. You do have that spider fuel injector inside the manifold they do go bad all the time. Thanks for watching

[@Aero_HER_Dynamic]

The G Automotive And More I took it to PepBoys for a diagnostic. He said the coil pack is bad....

[@TheGAutomotiveAndMore]

@@Aero_HER_Dynamic ok

[@juantrejo7084]

The injectors on the 4.3 liter engine they go inside the intake manifold and is a very commun problem, the injectors go bad all the time because was a bad design.

[@comaradelee]

At 1:55 is that the engine mount heat sheld from the driver side? I have recently removed the old engine mount on the driver side. After replacing the new mount. My engine started to vibrate in N and R, specially on R it sounds like vibrating. Could this be the issue, It might have pulled off? Since the engine was jacked up abit to remove old. Engine mount?

[@TheGAutomotiveAndMore]

Yes that is the motor mount heat sheild. It is possible that the wire got pulled. Thanks for watching.

[@keithlewis9106]

I have a misfire on 7, changed coil , wire, plug and injector, still the computer pick up a misfire , I lost what to check now. Any clues , grounding ?

[@TheGAutomotiveAndMore]

I would check the compression on that cylinder next.

[@rahrah8076]

Keith Lewis bad lifter maybe

[@DAREALCOUP]

Where is that harness running to or from? Hard for me to see in the video. So im having trouble locating it on my truck. Thanks in advance

[@TheGAutomotiveAndMore]

Its the ground wire at the left front of the engine. In front of the motor mount.If you remove the plastic shield you will be able to see it. Thanks for watching

[@DAREALCOUP]

@@TheGAutomotiveAndMore thanks so much

[@keelancampbell9808]

@@TheGAutomotiveAndMore hey how do you get the plastics piece off

[@TheGAutomotiveAndMore]

@@keelancampbell9808 If you are talking about the plastic shield its held on with 15mm headed bolts. Thanks for watching

[@keelancampbell9808]

@@TheGAutomotiveAndMore thanks I appreciate it and the video. I think I have the same thing going on with my truck it's a 2012 silverado. I have p0300 code. So I changed plugs and wires and checked coil packs. Then I took fuel rail out and cleaned injectors and put new o rings on. My next step was compression test but when I took out new plugs the driver side plugs hadn't been fired but the other side had so I'm going to try this. Hopefully it works. Thanks again.

[@mjwheelz1406]

What year was this?

[@TheGAutomotiveAndMore]

I think it was a 2011 or 2012 but the early ones have this ground also. Thanks for watching

[@jimmyramirez8844]

Was It running roughly and hard start ?

[@TheGAutomotiveAndMore]

Running real rough and check engine light on

[@jimmyramirez8844]

Thanks I will try tomorrow morning

[@templargold6722]

The trucks running ?

[@TheGAutomotiveAndMore]

Obviously you didn't watch the whole video because I stated at 3:48 that "the truck does starts now".........

[@alviadabrand6233]

this just went bad on my 07 yukon shop ran new ground

[@TheGAutomotiveAndMore]

These trucks are getting rusty now and are having ground problems. Thanks for watching

[@guadalupeperezjr8614]

What were the symptoms on your yukon?

[@gardud7]

So did that fix the truck? Never heard it run

[@TheGAutomotiveAndMore]

Yes it did, the wire was corroded and broken in the connector.

[@gardud7]

I have a 2005 GMC Denali. I'm having issues with multiple misfire code. I checked all the grounds I could find, including the one you show in this video. I removed and cleaned the ground wires and reinstalled them tight and checked them for damage. I am still getting a random misfire code. Any advice??

[@TheGAutomotiveAndMore]

@@gardud7 Could be anything. Bad coils, plugs, wires, and even a bad cam or lifter. You need a good scanner that can give you misfire counts so you can hone in on the cylinder.

[@melitonrodriguez7643]

I bet u replace your Gas cap and your problem solve Most of the times air goes into the tank and it causes your light to go off and then other lights and then by time you think you got a lift the problem because it’s running rough for idle check your gas cap

[@TheGAutomotiveAndMore]

This was not a gas cap problem

[@joekillingsworth9002]

@@TheGAutomotiveAndMore I changed plug & wire on #5 it showed misfire on that cylinder. Now it says random misfire. Now what????

[@TheGAutomotiveAndMore]

@@joekillingsworth9002 Do you have spark out of the coil ? I would get a scanner that can show the miss fire counts so you know what cylinder is missing. Have you done a compression test ?

[@melitonrodriguez7643]

@@TheGAutomotiveAndMore My 2007 Chevy Tahoe did the same exact thing and the dealership wanted to charge me arm and legs and toes and fingers and then all of a sudden Lee I check the gas cap and it was loose and I we replaced it and every light went off and it ran normal so yes in my case that was my problem

[@melitonrodriguez7643]

@@TheGAutomotiveAndMore And we did buy $150 scanner and it said all kinds of stuff on it though but like I said my girlfriend check the gas cap and it was looser than hell and we replaced it and everything rent went to normal after about 15 miles every light shut off car ran smooth everything Air was getting into the gas tank that was causing all that to happen

[@KevinHarris-hg9hr]

K

[@livefreeordietrying7242]

Good morning y'all I have a 2001 CHEVY TAHOE 5.3 vortex it has been sitting for over 18 months 😱 thanks to 🐂💨💩 of being sick Gas ⛽ and other crap💉 So money was every LOW🤦 I did keep up with the Driving up and down the driveway every 2or 3weeks but this morning she she didn't want to move in reverse, So I took out the the code reader and sure enough 3 codes came up P0300 and a multiple misfire and something with the EVAP. I'm going to try and get this worked on in a few minutes. If not then to the shop she will go💸💸🤦

[@TheGAutomotiveAndMore]

Check for mouse damage sense you have not really been driving it. Thanks for watching