Come Along with Eric O. as he has a look at this 2005 Chevrolet 1500 5.3 that has a symptom of low cylinder contribution. Not a dead miss but a "slight miss". Gathered some surprising evidence when we scoped the fuel injector to get a waveform.
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49 thoughts on “Gm 5.3 low cylinder contribution – failed injector”
  1. Avataaar/Circle Created with python_avatars Mechanic and skills says:

    O.M.G a labelled fuss cover with numbers and words and everything !!!!

  2. Avataaar/Circle Created with python_avatars Nicholas Frank says:

    I've got misfires on cylinders 1 3 5 7 I pulled valve cover no collapsed lifter coils sparks and wires appear to be fine….. 2007 suburban 5.3

  3. Avataaar/Circle Created with python_avatars Gökhan Özdemir says:

    I just wonder about your comment about my issue regarding a particular misfire for cylinder 2 for the 2017 Kia Optima Hybrid ( the bad thing is the injector plugs are not accessible without removing the intake manifold. Followings are what I did so far: 1. Cylinder Compression tests are done and all-around 180 for Kıa Optima Hybrid. 2- Cylinder Leakage tests are done with no head gasket issue. All leakages in %2 to % 4 for all cylinders. 3 – All spark plugs end Coils were replaced with OEM ones. 4. I tested ınjector 2 because there was a P0202 error and I also tested it outside of the car. I installed a new injector too. P0202 is removed, But still, I have a misfire error. The cables look good from the outside there is no damage but I am guessing maybe a broken injector ruined the ECU injector transistor. The worst thing is the problem does not occur permanently, it comes randomly. I use Autel IM508 to test while driving as well. Missfire counts randomly and I feel the rough driving. I also have Cat P0430 error according to the error. When I see this error I also thought maybe the injector working fine but ignition coil firing has the issue. I eliminate many things, now I am thinking 3 reasons: Injector cable harness, Ignition cable harness (it is not separate and I have to replace all engine harnesses), Faulty ECU.

  4. Avataaar/Circle Created with python_avatars Chuck Reed says:

    I just fix cars for family and I always enjoy learning as much as I can about testing electrical components. Also like to here your thought process as you take us through the diag.

  5. Avataaar/Circle Created with python_avatars Luis Valenz says:

    Great job troubleshooting sir

  6. Avataaar/Circle Created with python_avatars Bruce Bratschi says:


  7. Avataaar/Circle Created with python_avatars alan chambers says:

    Diagnosed 1 on a quest by isolating cylinder by disconnecting coils, determined it wasn't spark so I unplugged injector, no drop in rpm. New injector fixed problem, luckily it was a front one.

  8. Avataaar/Circle Created with python_avatars Terrell Stevenson says:

    I Have That Exact Problem P0306 P0200 … Injector It Is

  9. Avataaar/Circle Created with python_avatars Donald Rackley says:

    Give me more diagnostic video Mr owe. Bring it on boy. Great as ever

  10. Avataaar/Circle Created with python_avatars efilnikufecin2004 says:

    I have encountered a bad injector on a 01 Silverado. My problem was extended crank time. The classic loss of fuel pressure a short time after key off. In my diagnostic process i pulled the fuel rail with injectors and had the wife turn the key on. I watched the injector spray. I went ahead and replaced the fuel filter out of caution and popped in a known good injector out of my old truck I still had.

    I also was not expecting a bad injector, but wanted to eliminate other possibilities before replacing the pump which the previous owner had already replaced for other reasons. He sold the truck because he thought the pump was bad and didn't want to replace it again.

  11. Avataaar/Circle Created with python_avatars Garrett Arney says:

    Newer 5.3 like probably 2014 up that body style I’ve done multiple sets those years I’m not sure I’ve ever seen one fail

  12. Avataaar/Circle Created with python_avatars Leigh Pike says:

    Had almost identical misfire on a 3.0 chev gdi motor, for some reason it was sticking open erratically. Just lucky to find it .

  13. Avataaar/Circle Created with python_avatars Jarle Gregersen says:

    I am using a IR gun on the manifoil,straigt out of the head.
    easy to find the problem cylinder.
    Rich is cold,lean is hot.

  14. Avataaar/Circle Created with python_avatars Nebur Salcido says:

    Talk much

  15. Avataaar/Circle Created with python_avatars Nebur Salcido says:

    U n Ivan should get a room😂😂

  16. Avataaar/Circle Created with python_avatars Jack Erckman says:


  17. Avataaar/Circle Created with python_avatars Nicks autorepair says:

    Great video as always. In the last 11 years of having my own shop, also in truck country with lots of chevys. I can only recall encountering 2 different trucks with a bad injector. 1 was a Tahoe and the other was a 1500. Both were 5.3 Z engines. It was back before I got handy with my scope. I used injector balance test and resistance to diagnose them. If I’d started watching you and scannerdanner sooner, I would’ve been able to diagnose them faster. Thanks to your videos, my scope stays pretty busy these days. Thank you.👍

  18. Avataaar/Circle Created with python_avatars ralph1bart says:

    Keep up the in depth current and voltage waveform diagnostics! The amount of information you can gather, both precise and relative is fantastic.

  19. Avataaar/Circle Created with python_avatars TheAussieonvanisle says:

    Interesting that you comment about people replace injectors without proving it, seems to be the norm more often than not. I had the same model come to me after injectors had previously been replaced but the rear injectors on both sides "failed" again. Turns out there was sediment in the rails and yup, they slope down toward the back….apparently the owner thought the fuel filter was life time because they were steel not plastic lol.

  20. Avataaar/Circle Created with python_avatars J says:

    Yooo Eric O, I'm looking at an 07 5.3 with a P0300. I'm just a newbie in school but I got my hands on a Solus Edge this weekend only! Fixed an exhaust manifold leak and pcv hose leak which helped quiet her down a bit. Still random misfire. Plugs and wires are newer and test good. Clean maf/throttle body. Solid fuel pressure. Intake doesn't seem to have a leak. Any advice for this Solus Edge?? Thank you so much

  21. Avataaar/Circle Created with python_avatars Kevin Williams says:

    I have a 2013 1500 Chevy I have a cylinder 7 misfire. I found and replaced the spark plug due to it being broke however after replacing the plug and eliminating back coil by switching #1 &7 coil and still getting the #7 misfire Eric do you have any ideas

  22. Avataaar/Circle Created with python_avatars Robert Dunn says:

    I know you probably wont see this since its 3 years old but I actually had it happen the other day I works for a bus / car fleet we have e450s with 5.4 and chevy caprices with the 6.0 and the 3.6 so the 6.0 had a cylinder 2 misfire co worker of mine did tune up still had the mis changed the coil I came back from working in one of our other shops a week later re confirmed the mis on cy 2 checked out the data found my fuel trims were high went to ignition coil just to double check its firing correctly with my scope then went to the after the injector with the scope it wasn't till I found the shorted coil that the injector wasn't opening causing the high fuel trims I've been trying to break out the scope more this is my second diag performed with strictly scope but because of guys like you scanner danner and the wells videos I'm starting to pick up on things it's not the most perfect training source but it's getting me places thanks for the videos yall really help people who cant get to a real hands on scope class

  23. Avataaar/Circle Created with python_avatars Erik Johnson says:

    Why do people complain if the content isn't what they want? It's baffling to me. Go elsewhere! There's tons of crap on YouTube, for cryin' out loud, like 1000 videos on every topic! Eric, your channel is my fave, bar none. I hope you'll ignore the complainers. I just don't get it.

  24. Avataaar/Circle Created with python_avatars Brian Mason says:

    I'd be with Michael Berg….yes I like seeing you fix stuff, but I prefer the scope, DMM, scan tool diag videos as well. Previous employer had a 4channel Pico, I'd be pulling it out to use anytime I could come up with any excuse to.

  25. Avataaar/Circle Created with python_avatars Cjay Jayjay says:

    Enjoy the diag videos thank you

  26. Avataaar/Circle Created with python_avatars Jenn Cox says:

    I am in awe of your physics and electronics knowledge. Most mechanics wouldn't know Ohms law if it smacked them up side the head.

  27. Avataaar/Circle Created with python_avatars Sarah Sargent says:

    As always Moro v good

  28. Avataaar/Circle Created with python_avatars Clifford Hill says:

    Of all the videos you do, I think I enjoy the Diagnostics videos the very most. Keep it up Eric.

  29. Avataaar/Circle Created with python_avatars It's Not THAT Complicated says:

    Great job showing the Hows and Whys of misfires and fuel trims. It’s amazing how many “mechanics” don’t know the concept behind long and short term fuel trims, or how many don’t understand how a GM EVAP system works…. unbelievable.

    Thanks for all the quality content.

  30. Avataaar/Circle Created with python_avatars Thomas Sears says:

    My 99 5.3 did the exact same symptom and it was an injector

  31. Avataaar/Circle Created with python_avatars The Radio Mechanic says:

    The only guys who are going to complain about diagnostics are the parts cannon guys. They just want to know how to cram more parts in the cannon.

  32. Avataaar/Circle Created with python_avatars Michael Pistilli says:

    Disconnect the suspect injector see if fuel trim changes and monitor o2 sensor and misfires

  33. Avataaar/Circle Created with python_avatars Greg Leithoff says:

    Another good one Professor O!,,

  34. Avataaar/Circle Created with python_avatars GNX157 says:

    Definitely would of advised the plugs and wires, as well as fluid change in the diffs, transfer case and transmission, based on that mileage. Although rare, I would of at least discussed replacing all injectors, if only because they fail so rarely, but whatever this injector was exposed to, so were the others, as well as probably being manufactured at the same time and maybe there was something going on in the manufacturing at the time.

  35. Avataaar/Circle Created with python_avatars Willie Gillie says:

    Diagnosis are my most favorite videos. I like the way you describe what should be happening and what is wrong on the wave forms. Can tell you’ve been at it long enough to know what you are looking for. Your setting a good standard for others to follow. For sure my most favorite videos are the diagnostic videos

  36. Avataaar/Circle Created with python_avatars Derrick Odyes says:

    seen those fuel lines rust internally anf send rust into injector screens causing misfire from lack of flow. Fixed by r and r lines and clean fuel rail and injectors

  37. Avataaar/Circle Created with python_avatars Kelly Burgess says:

    People will whine about anything. If the video helps just one person facing this problem, the video is worth the effort

  38. Avataaar/Circle Created with python_avatars kalkhoven89 says:

    Great video thank you. I don't get many misfires in the shop but I'll sure be ready for when they do roll in.

  39. Avataaar/Circle Created with python_avatars Greg Sullivan says:

    FYI, I'm in Australia, and have the '17 Holden Caprice, which has the LS3. 97,000km on the clock, and THREE injectors have failed so far, and I think a 4th is on the way out too. (misfire codes on #6). Usually, I get both a misfire code, AND an "injector circuit fault" code, however so far, #6 is only reporting misfire. Dealer said it's a reasonably common problem at the moment, on high usage vehicles such as mine (I'm a limo driver), and police vehicles etc. They also say the coils are going high impedance, not low, like yours.

  40. Avataaar/Circle Created with python_avatars Duncan Mac says:

    Thanks for the video.

  41. Avataaar/Circle Created with python_avatars DirtyFingernails Auto says:

    I havent seen many injector failures on these motors , actually GM in general I havent seen many