2004 Chevy Impala Misfire (Oops)

[@kenr.4526]

You may have just solved the "mystery misfire" for me and thousands of viewers. Happened right after I had some work done. Took it back in and after a week nobody could figure it out. I wouldn't think this was even possible and the techs who worked on it must not have either. Eric and Ivan were right about you Keith. Outstanding !

[@pinpointautomotiverepair1592]

Great lesson! Sometimes when things may not make sense you need to slow down and weigh all the possibilities. Utilizing cylinder contribution showed the problem but one would need to take their time and really analyze what the scan tool is telling you to catch it. Thanks!

[@juanrodriguez-ry6yt]

finger nail paint comes in many colors i have been markings vacuum hoses and wires for longer than i want to say.another good lesson thanks amigo.

[@skee0310]

I like to use telephone wire , we call it marking wire. You can get a big bundle of used telephone cable for the telephone company just cut it down to size , there are tons of small wires inside with tons of colors. It works great for me.

[@billrimmer5596]

I don’t what to say. Every little tidbit of info u give us is really appreciated. Even what u consider mundane, hit us with it. We will enjoy it. Remember I’m still tryin to figure out my Vantage MT 2400. Histograph. Wave form viewer etc. Trigger, slope. My mind is spinning!!

[@bobmoy3406]

Things are not always what they appear to be. Great explanation and thanks for binging us along.

[@kennyb1155]

Yes Keith, anyone can own a scan tool BUT you have to know a basic understanding of what it its your looking at. Great fix sir 👍🏻🇬🇧

[@joemikos900]

Very grateful that you stop and take the time to make these videos Keith. You save many of us techs hours of frustration and time. TYVM again! Say "hi" to Rocco.

[@DavidAusman]

Different mechanics have done this to me twice now on my 2001 Chevy Monte Carlo 3.4. Just had some work done and now it’s the third time with crossed wires. Grrrr...bringing it back in. Thanks for the great video.

[@ozzstars_cars]

We have all crossed a wire wrong at one time. Good explanation of the problem Keith.

[@mikeeustice4452]

Great find. To further prove it you could put a pressure transducer in the spark plug hole and get a second channel on the injector and verify if its timed just before the intake stroke

[@seanmiller6495]

Im dealing with this right now..ive been trying to learn this for while..and you made it easy. Thank You

[@haywardsautomotive6156]

Nice diagnosis Keith! That'll blow the normal diagnostician's mind unless he has kept an open mind to all possibilities.

[@darrellasbury5781]

This is real world stuff,thanks for the explanation of the process.

[@satamanschmidt3428]

Keith, the car whisperer.

[@NewLevelAuto]

+SATAMAN Schmidt sometimes I yell too , but either way its gonna get fixed 😄

[@billmaxfield7831]

Hi Keith it's really great how share your wisdom with us all. Thank you so much. Great job on that one brother!!!

[@billyyoder8171]

Thank you Keith. Appreciate you sharing. Great job.

[@arthurfricchione8119]

Good video Keith. Really never saw one showing injector harness connectors swapped. Nice info to keep in brain storage thanks 👍

[@Theyhatelonzo]

Mine isn’t throwing codes or check engine but it’s jumping and shaking at stops.

[@josephwash109]

I replaced the intake manifold gasket set on a 3.1L not long ago, and if I remember right there was hardly any slack where the injector pigtails came out of the main harness. Someone must have done something weird with the harness to cause this issue. In my case, the electrical tape was hardened to the point that it kept the injector connectors in their intended positions. Nice find!

[@davidsajak9050]

It seems hard to believe that you can open that harness up enough to even get enough slack to reach cylinders 3 to 4.

[@HardKnocksForge]

I bet that’s more common of a problem than people think. I’m always marking plug wires and injector wires for that reason. It’s just too easy to get them mixed up.

[@NewLevelAuto]

+Hard Knocks Forge absolutely brother. All it takes is being pulled away from the car for a phone call or question and accidents happen

[@tonypond8196]

excellent diagnosis ! thanks for taking the time to share this .

[@jamesh6229]

Thanks Keith, Crossed spark plug wires on a 73 Ford pickup once, pulled my hair out before it was discovered (by someone else). It's best to check the basics.

[@zombietherapy1759]

watch the people at auctions playin around under the hood. just sayin!

[@arcadeuk]

Many years ago, I managed some cars. An employee was leaving so he hands his car back. I took it out for a drive and it ran pretty rough. Found out that 2 cylinders were swapped (on a 4 cylinder engine) and he drove it like that for aprox 70,000 miles! I have no idea how he could have put up with it for that long, it was really noticeable and smoked like a tractor. This was a car that had driven from brand new and had an engine failure at around 20,000 miles. The injector swap we assume happened when the engine was replaced, and he ran it like that till 90,000. Savage!

[@stephenjackson4392]

I have a 2004 Chevy Impala with a 3.4 L. I had the code and replaced the coil pack , wires and plugs and still had the misfire and code. Mind blowing . I pulled the power steering pump up and found the 3 wire plug in connector going to the Cam sensor had all the insulation on 3 wires had rotted off from heat and all wires were touching ea other. Repaired the wires and misfire code gone

[@garageworker]

Years of experience and logical thinking, bravo!

[@ryans413]

It written right on the coils 1-4 2-5 3-6 back bank is 1 , 3 , 5 front bank is 2 , 4 , 6 it’s not hard to mix this up if you just look at the coils

[@baxrok2.]

When isn't cyl #3 number 3? When it's #4! Great diagnosis sir. Thanks!

[@rlacroix4]

I battled with PO301 on a 2003 Impala same engine. After 3 months external parts swap and changes. All kinds of high octane gas, boosters, and cleaners. Code return in > 5 mins of reset and sometimes flashing CEL. At end, I took to shop and had 2 shops diagnosis it as leaking valve(s) and needed a valve job. Low compression on Cyn 1 (90 psi). Pep Boys and another independent shop. ( I always get a 2nd diagnosis before spending a large amount of money) I had tried all external parts change and swaps before going to shop for diagnosis. ( $2600 at PepBoys or $600 in Tijuana Mexico for Head/Valve job. And in Mexico I can supervise all work and watch. Even help! But the cost of head job exceeded the value of the car. Waiting for rebates and new car deals to trade in the car for a new one. I frustration I happen to watch a video of a guy using Sea Foam in his old truck on youtube. It was June 2018 and I needed to dump car due to CA song test in November 2018. So I had a few months to shop. I bought Sea Foam and put in gas. By 1/2 tank CEL off. Passed CA smog test 2 weeks later as all IM monitor test passed. Now have used about 5 cans of Sea Foam in tanks of gas. Put 10K miles driving daily 200 miles a day from Disneyland to Tijuana. NO CEL in 10k miles. It was later discovered that the owner ( Mom) used exclusively Costco/ Sams gas for since new for about 86k miles. Sea Foam company has not offered an explanation other than thanks for the report on the good news and success. Looking for theory on what happened. My thinking is Costco / Sams gas does not have enough detergents. And the Techron and Walmart injector cleaners I used once a year were not enough or correct formula to cope with build up. Sea Foam fixed it a P0301 that must have been caused by excessive carbon sludge build up on a valve. Sea Foam does not comment much as to explain possible cause and effect. Yes I am happy, and kept the car as a daily driver driving 90 miles one way to work each day. Very curious. This was moms car but she died of cancer this year. Gave me this car to use, sell, or junk. 2003 Impala with 86k miles. Now got 102500 miles and NO CEL since Sea Foam. Still waiting for this engine to blow up and I will just leave the car on I-5 and call a Uber. But it runs so smooth. Any ideas what Sea Foam did?

[@scottpearsontoolsmore185]

Great video thanks brother. Thanks for the info and explanation. See you in the next video thanks again

[@kennydoolarchan9515]

Thanks Keith for sharing this video.

[@NewLevelAuto]

+Kenny Doolarchan my pleasure , glad you liked it

[@markferraro5250]

excellent video Keith thanks got me thinking

[@DonDenaBrenna]

i had coils switched on a maxima one time, had that cat glowing red! Shit happens just gotta go back to basics almost every time or to the last thing touched!

[@adamtrombino106]

On older OBD 2s, I never trust scanners as far as misfire codes go. I verify that the code whichever cylinder, is actually misfiring usually by disabling spark, or an injector if it's easy enough. I've seen many cars, especially GMs, with lots of mileage set a 'false misfire code' IE wrong cylinder many times, while you can look at live data and see a completely different cylinder is actually misfiring. Now I can only assume that it might be due to chain slack or perhaps a cam/crank learn issue, but I always double check that say #3 is actually missing. As far as swapping the connectors, I didn't think that was even physically possible on the 3100s or 3400s, not enough slack in the harness.. But the next time I have to do a lower intake gasket, I'll have to pay attention to that! LOL

[@lillock16]

True just found my 3 and 5 crossed thanks

[@SAAutoRepair]

So he must've had another issue as the original complaint then? Logic says the injectors were changed to address an issue, the harness was swapped on 3 & 4 causing a new issue. No?

[@NewLevelAuto]

S & A Auto plug wires

[@roadkill5333]

As long as I have been watching these car repair vids, and I mean a long time, with ScannerDanner, Eric O. Ivan the Wonderful, and yes, you too, I just have to know how that you determined that the injector leads were swapped?? I'm mean, there is no way to see them! No way to swap them back! No good way to test this, unless you somehow go to the main harness, and know to search for this!! Was their some info that you have seen in the past?? Was there another clue? Did you search, and test and finally come to this decision?? Not that I'm doubting you!! Just curious as to how you realized this!! I'm thinking thru this issue, and am very familiar with this engine! Had a 97 Monte Carlo with the 3100, and an Olds Silhouette with the 3400, and have done many repairs to both, fixed many strange issues with both, and have figured out and fixed many odd happenings, even after a serious malfunction!! This would not have even come to mind, had I been looking for it!! And even with the Tech 2, I was not even prepared for what you revealed!! I will now and forever be looking for a simple solution to an extravagant problem, but not before this!

[@NewLevelAuto]

+roadkill5333 very simply put , I never trust cylinder identification on a GM. So I decided to kill an injector to verify tge code being set was truthful. I started going in order from one through 6 , but as you can see the other cylinders would not count because the pcm even in test mode was still focused in on that cylinder 3. But of course you can see the outcome here. Once I saw the killing 3 killed 4 , I rechecked firing order and moved on logically from there. He mentioned the injectors were replaced . Hmmmm 😉

[@Rustbox306]

I could be wrong but.. It could have been seen on injector waveforms and relating them to ignition waveforms. The vehicle has a specific firing order and the injectors are supposed to fire in that order as well.

[@roadkill5333]

New Level Auto thanks!!

[@NewLevelAuto]

vachon644 in watching an injector waveform relative to timing , remember that it can vary greatly. I look for the quickest and most definitive possible solutions in testing to keep up with the workload. No waveform necessary when we have the bidirectional control in this case

[@kdmq]

The fuel goes into the intake so really both 3 and 4 could still fire but they were running off stale fuel.

[@exmotorsports]

Great One Keith..something to remember for sure. Thanks Cheers..or Dunkins to you (:

[@Clonewarz901]

What if your getting all these symptoms but never touched the fuel injector connectors?? It’s cylinder 1 I can’t seem to figure out. Replaced the spark plugs, coil packs, and plug wires. New TPS and MAF sensors replaced intake upper manifold gasket but still getting it

[@ThePlowGuys]

Good find man.

[@kennypatrol2zero616]

I bet Columbo coulden't have worked that one out, That's your Jedi Traning coming into play again, we dont see many V6 or V8 in the uk ($8.50 a gallon) so we dont really see faults like that, but that was clever, cheers buddy

[@DylanRabier]

Nice one Keith! Thx 👌

[@NewLevelAuto]

+Dylan my pleasure as always

[@robinsonsmotorcycleandauto3929]

Great Video keith as always

[@themechanic6117]

Great info, thanks ! 👍

[@ggstephens50]

Keith was the car missing a lot on cyl 3? With the injectors 3 and 4 crossed both injectors would still be firing just out of time with their intake valve opening. Maybe a slight miss at idle but, did you try taking the RPM up to 2 grand or so? I think the miss would go away as air speed and valve action increase, the timing of the fuel spray to an open valve becomes less important. Such is the case with a old group fire setup, as in 1,2,3, and 4,5,6, injector pairing (Buick 3.0l) . Was cylinder 4 missing also?

[@bradlehman1537]

not sure if this is my problem, but I will keep it in mind, thank you!

[@jasonc.4683]

Hey what's going Keith? Is the tech 2 scanner u only have or do u have that just for gm. Just wondering so I can know what to get to for the future and what scanner do u recommend when I do decide to get my mobile stuff on the road. Thank u. Man u really are smart

[@GCraigmile]

Just move the 2 wires at the main wire connector and don’t even touch the Plenum or the intake unclip two wires if you know which two are backwards and plug them back in.

[@NewLevelAuto]

GCraigmile oh man the poor fella who might have to figure that out down the road though 😂

[@GCraigmile]

New Level Auto ,,,,Ya’ but the car should be scrap by then.. With that many miles on it all ready..

[@Blackmage50]

Great video! I spy an ATRA member! We're everywhere! Lol

[@diymisfit_Mechanic_UDX404]

Good one! Thanks for sharing

[@tashag.1972]

Hello! This is my current situation: 2005 Chevrolet Impala Codes P0300 P0036 P0140 P0141. Any suggestions?

[@EXOVCDS]

Very interesting & cool!

[@andrewthompsonuk1]

Would I be correct to say that it would not misfire if the cam sensor was unplugged? (Turn off sequential injection)

[@throttlebottle5906]

Gimpala is what I call them :) also, I bet the learn the injector wire color for 3 and 4 now lol!

[@aaronlisterman]

Thank you sir

[@jhuntosgarage]

This excellent info! Thanks for sharing!

[@billsmith2212]

Put brain in gear BEFORE firing the parts cannon ! Stop , look and THINK ! Anytime , Anyone touches Anything - it's open season for problems ! Very few " experts " take the time to put ALL the possibilities on the table and methodically check them off the list . Once the car is molested - anything is possible ! And the customer pays big time for the simple fix ! Thanks Keith .

[@63256325N]

Thanks for the videos.

[@t-rodshader9593]

Im having an issue with one now that feels like intermittently upon acceleration it loses all power and has a few pops from the exaust but then it will suddenly straiten out and run like new. Ive worked on customers cars that usually needed crank sensors or icm but this acts weird unlike ive ever seen. Not sure why. And at times it will act up at idle where it begins to have really really negative fuel trims and starts sounding like the timing is off. That tinny exaust sound. Its so intermittent that its hard to track and i just dont understand what all coukd cause it. I was thinking false triggering of a crank sensor but without a scope handy im not sure. I do have a scope but its in storage after a move quite a ways off. Any ideas where to start? Thanks in advance.

[@bennie1634]

Nice one Keith !!

[@dunntanktrucks]

same thing will happen on gm 5.3l ..... injectors 6 and 8 wires get swapped. sometimes only misses on deceleration or when goes into v4 mode

[@insurancedice]

I appreciate the video. If I only have a basic scan tool, is there another way I can do this test?

[@charlieburks606]

What kinda of Code Reader you are using?

[@wyattoneable]

That's a good one Keith!

[@int53185]

It's not idiot proof like the 3800.

[@mid-thumbautomotive9716]

Nice!

[@karlhonda9013]

Great video keith, you do have amazing talent keep up the good work.....question I got a 1998 honda accord 2.3 non lev. Just can't get rid of this dam hard trouble code p0135 at start up every time change 02 sen dealer , ecu, wiring great condition I am getting everything that I suppose except for p0135.. any help will be appreciated thank you. ...

[@BigDog50001]

Karl Thomas Assuming you checked all power/ground/signal wires/drivers and wiring integrity and also checked for any pin fitment issues, make sure the sensor is correct. Sometimes Honda uses an O2 sensor and sometimes they use an A/F ratio sensor on the same model (the engine codes on the block will be different).

[@karlhonda9013]

Big Dog50001 Automotive thank you for responding to my issue, I am having for several years now.. everything you mentioned I check the driver is just not turning on if does, it constantly on without a pulse from the driver just wired.. I am a D I Y that won't give up very very determining thank you. ...

[@deepsquat600]

DAMN I am good ..that was the first thing I thought of ( been there done that LOL )

[@777gearhead]

great video Keith. where is the best place to get a gm tech 2 scanner and is there anything to look out for when buying one? thx

[@MURDACIDEBOY]

is this 3.4 or 3.6 ?

[@Fosschad]

3.4 or 3.8 they made them with both newer impalas have the 3.6

[@donnierobertson3088]

Nice job

[@philh9238]

3:10 give away injector connectors are swapped cyl#3 cyl#4

[@smms1276]

Good one thanks man

[@tgoodm1]

So I take it this was not a quick diagnosis.

[@richardcranium5839]

you would think they'd route the harness and make one side shorter so the wires wouldnt fit but that would make sense. now if you really want to screw someone up swap the wires at the ecu plug. lol be easier to get to

[@ColdWarVet607]

Scan tool code not well written or needs better hardware or CAN buss not enough bandwidth. Its like the tool is sucking all CPU power looking at the misfire, probably a bug in the code.

[@NewLevelAuto]

So many bugs in the tools I could write a list on 1000 sheets of Scott paper

[@ColdWarVet607]

Bet ya could write 2000. A program or tool is only as good as to the extent its tested or verified. Seems you have found that extent pretty well many times over! Why dont you make another video "Scanners that Scan but Can't See".

[@nickcove7355]

Not very often that they design an injector harness that can actually reach an incorrect plug. Labeling would help. Hey nobody ever said GM was perfect. Ever. XD

[@LSCHEVYRYDER254]

hey new level when you get a chance swing by my channel i have a 1991 buick Riveria 3800 after it warms up seems to not be sparking after it gets warm not sure if icm or where to go from there

[@yanierolivera4678]

💪👍👌

[@ggstephens50]

Scan data is only as good as the tech using it

[@Imma89Star]

All y’all do is talk is circles bro!! Maybe point to the scanner and than point too on the car what that means

[@HouseCallAutoRepair]

Thank you, thank you, thank you! We NEED you back!

[@SantosGonzalez-e4k]

Good

[@busbqbill449]

nice

[@allenk5649]

Doh!

[@amandocontrerasgarcia9380]

Time luse!!!