2016 Tahoe Misifring

[Peter Smith]

I have a 2016 Tahoe with 110,000 miles that is misfiring on number 8. It has been doing this intermittently for the last 10 months. I have had it at the dealership 6 times for this problem. The first time, 10 months ago, they replaced the plugs and did a "engine and injector cleaning" which did not solve the problem. I can go weeks without it misfiring and then it will do it 2-3 drives in a row. Most of the time the code does not stick but rather just flashes. It is currently at the dealership and this time the code light was stuck on. My frustration at this point is that while the dealership has the data that it is misfiring, they keep telling me they cannot recreate it and so don't know what is causing it. They have had the car for two weeks at this point and the last four times it has been in for this they give up and tell me they can't figure out what is wrong. At about 30k miles it was randomly misfiring and they replaced all the injectors as a warranty issue.  I am getting ready to go to a different mechanic/dealership but wanted to know if anyone had any insight for me. I have attached the mode 6 data from my code reader that triggered the engine light this time.

[Jsdirt]

I feel like a broken record telling hundreds of people this every month ... but GET THAT THING OUT of the dealership!! You're way out of warranty, and the way GM corporate's trickle-down business works, you will be paying THOUSANDS with no solution (except for a shiny new POS for $60-LARGE out on the lot they'll gladly sell you ...).

 

At the mileage you're at, I'd bet that you have a partially sticking AFM lifter. Ticking time bomb waiting to stick solid and misfire constantly. They all do it eventually. Of course there could be leaky intake gaskets, wiring issues, and several other things that could cause this. You NEED to get that thing out of there and into a reputable INDEPENDENT garage. trust me on this. I see and hear this same old story play over, and over, and over again year after year. These days dealerships seem to be on the same level as politicians. Insanity ...

Edited November 15, 2020 by Jsdirt

[Doug_Scott]

This will be a bit more positive message.  Personally, I would rather have the shop tell me they can't duplicate the issue than start throwing "best guess" fixes at it. 

 

Having been a mechanic, I would tell the customer that I was not able to reproduce the issue if the issue did not happen.  I also would explain that without experiencing the issue it would simply be a guess to offer a diagnosis. I would suggest they take their vehicle and pay attention to what they did to make it appear.  Once they find the way to reproduce the issue, verify a few times that those steps cause the issue to return then bring the vehicle back.  To me, the only thing worse than being wrong was getting caught when wrong. 

[Jsdirt]

That's what a trip to the dealership usually leads to - thousands of dollars in parts fired out of the parts cannon with no resolution! Like I said - same old story over and over again.

 

Even service data tells you to grab a good part and replace the part - if it works, it's good! No in-depth diagnostics. "Does 'part x' work? Replace ECM" - insanity! Good way to keep GM stockholders and their vendors happy. GM doesn't even like backprobing connectors! How the hell can you even troubleshoot without back probing a weatherpack? Plus they don't pay the techs for the time required for any in-depth troubleshooting (that isn't even taught there to begin with), so why would they bother? I wouldn't either. I don't know of a single person who will work in this field for free. It all starts at the top, and rolls downhill unfortunately. You know the game. Gotta play it if you want to eat that week.