Looking for advice on misfire codes while truck at dealer

JoJo1 · October 30, 2022

I have a 2021 Elevation 5.3L with 45k miles. I was brought in at 40k with a steady check engine light (P0300 code) that didn't turn off on it's own. Misfires on multiple cylinders. They cleared the code and it hasn't come back, but I just brought it back for the 45k mile oil change and asked them to look at the engine again and even though the steady light hasn't stayed on, but it recently flashed on and off and then stayed off, but must have left the history on the read. Right now the truck is at the dealer and they're trying to figure out the problem...

So after doing some research on my own, it seems like a bunch of similar trucks have been having lifter issues, pushrods, fuel injectors, etc. all associated with the AFM and DFM. I have two major concerns. One is I'm approaching the end of my factory powertrain warranty and the other is the reliability of breaking down on a roadtrip with my family.

I read that there's a class action lawsuit against GM, but no recall issued and there's also a bulletin to replace just one side of the lifters. Also some talk about GM extending the warranty to 100k because so many have had this issue.

What options or leverage do I have at this point? It says my trade-in value is around $40k to $42k, but new truck prices are just insanely high, so a trade-in is not a great idea. Do I have any leverage to try to get GM to replace all the lifters and not just the one side? I did purchase an extended warranty when I bought the truck new, but not sure about the exact coverage on this stuff. I'm going to review that contract to see what the details say, but can get something seperate from GM to cover this problem if it fails in the future?

The dealer didn't come back to me yet with a diagnosis on the problem(s), but I want to be ready with my options before calling them tomorrow morning.

Any advice is very helpful. Thanks!

RobZ · November 15, 2022

I had check engine light come on with cylinder mis-fire, but the truck also ran like ******. both times required lifter replacement. I too am asking GM to extend warranty as I now have 69000 miles

slj2008 · November 15, 2022

which engine do you have ???

newdude · November 15, 2022

On 10/30/2022 at 11:19 AM, JoJo1 said:

I have a 2021 Elevation 5.3L with 45k miles. I was brought in at 40k with a steady check engine light (P0300 code) that didn't turn off on it's own. Misfires on multiple cylinders. They cleared the code and it hasn't come back, but I just brought it back for the 45k mile oil change and asked them to look at the engine again and even though the steady light hasn't stayed on, but it recently flashed on and off and then stayed off, but must have left the history on the read. Right now the truck is at the dealer and they're trying to figure out the problem...

So after doing some research on my own, it seems like a bunch of similar trucks have been having lifter issues, pushrods, fuel injectors, etc. all associated with the AFM and DFM. I have two major concerns. One is I'm approaching the end of my factory powertrain warranty and the other is the reliability of breaking down on a roadtrip with my family.

I read that there's a class action lawsuit against GM, but no recall issued and there's also a bulletin to replace just one side of the lifters. Also some talk about GM extending the warranty to 100k because so many have had this issue.

What options or leverage do I have at this point? It says my trade-in value is around $40k to $42k, but new truck prices are just insanely high, so a trade-in is not a great idea. Do I have any leverage to try to get GM to replace all the lifters and not just the one side? I did purchase an extended warranty when I bought the truck new, but not sure about the exact coverage on this stuff. I'm going to review that contract to see what the details say, but can get something seperate from GM to cover this problem if it fails in the future?

The dealer didn't come back to me yet with a diagnosis on the problem(s), but I want to be ready with my options before calling them tomorrow morning.

Any advice is very helpful. Thanks!

I'd see what they find and start a case with GM customer svc. If you are planning to keep the truck, tell them you are concerned of a repeat failure and that you'd like to see if GM could provide some sort of extended powertrain warranty on them for peace of mind. If its a bad lifter, could you try and see if GM would replace all 16? Worth a try, but no guarantee on that one.

If its a bad lifter on one bank, GM wants the dealer to replace all the lifters on just the bank that had the failure. If you have a bad lifter on both banks, you'd get all 16 replaced.

RobZ · November 17, 2022

On 11/15/2022 at 4:27 PM, slj2008 said:

which engine do you have ???

2019 L84 5.3 v-8 with DFM

John813 · November 22, 2022

Yea, it's lifters. It's unfortunately not a rare failure for these trucks.

For what ever it's worth, my fathers trackhawk had it's lifters go out at 105k, and it has no deactivation. They replaced all 16 under extended warranty no questions asked. 6.4L Hemi SRT I had went out at 72k. So, while not a huge case study lol, but it seems any OHV can have them go out, DFM or not.

As long as you have a good extended warranty company, lifters should be covered.