Cylinder 1 Misfire trouble shooting...

Ozer · January 12, 2020

Having the exact same issues. 2017 Sierra z71 crew cab. Truck has 40k miles. Throws codes for misfires and rough idle. Got an email from gmc about a emissions issue. Every so often after pulling out of my driveway, the traction control light will come on and go away. When this happens, the truck will slam down gears from 3,2,1 then surge on take off. It’s hit or miss but frustrating as hell. Truck has been parked for a week. I just scheduled an appointment at the dealer because I’m fed up with this pos. I have a 100k mile power train warranty. Hopefully it’s a simple fix but I’m not willing to dish out any money out of pocket for what is essentially a brand new truck.

That is identical to my issues. Please reply back when you take it in. I don't want to throw money into injectors if that doesn't end up being the issue.
I'm at 131k so no warranty for me.
They will tell you you have to agree to pay the diognastics fee, just say OK. That will be covered by the warranty work when they fix it.

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Ozer · January 15, 2020

Update on my issue:

The day i did the compression test i also swapped out the #1 and #3 spark plugs and wires and while i was there i installed one of the old but still good coils into #1.

Even though all 8 coils are new i figured why now. Its been 4 days and no issues so maybe it was the coil acting up? The scanner showed they were all working fine so not sure.

I also have been running seafoam gas treatment 2 bottles in 1/4 tank till almost empty so the concentration is higher. Maybe that helped the injector?

Lots of maybes here but day 4 and no issues, will report back if it acts up again.

I'd like to know what @kevin wright reports back with his identical issue.

MonkeyMouth · September 23, 2020

Any updates?

Vandy2596 · September 24, 2020

I am having similar issues with my 2014 Silverado. 115k on it, changed the plugs and wires at 110K. RPMs jump every now and then at idle and it will idle rougher than usual and throw the check engine light on and the traction control light on. It will shift up and down hard through the gears at low speeds. Code says cylinder 2 misfire, I've replaced the coil and experienced no change in idle. The lights usually go away on their own and everything goes back to a normal slightly jumpy idle. I haven't experienced any loss of power while accelerating or driving at highways speeds, just the rough idle. Hoping its not an injector issue, running sea foam at the moment.

Interested to see what the dealership says the issue might be. I'd like to avoid bringing it in myself if i can

flyingfool · September 26, 2020

anyone know what cylinders are AFM?

MC_ · August 19, 2021

On 1/12/2020 at 12:23 PM, Kevin Wright said:

Having the exact same issues. 2017 Sierra z71 crew cab. Truck has 40k miles. Throws codes for misfires and rough idle. Got an email from gmc about a emissions issue. Every so often after pulling out of my driveway, the traction control light will come on and go away. When this happens, the truck will slam down gears from 3,2,1 then surge on take off. It’s hit or miss but frustrating as hell. Truck has been parked for a week. I just scheduled an appointment at the dealer because I’m fed up with this pos. I have a 100k mile power train warranty. Hopefully it’s a simple fix but I’m not willing to dish out any money out of pocket for what is essentially a brand new truck.

I have a 2016 Chevy Silverado doing this exact thing Cyl 1 misfire code, engine light with the traction light and all. A mechanic worked on it last year and did the overnight compression check since nothing changed after swapping the plugs. Changed a coil and I've been ok for a year. Now the same problem all over again. I even have that sudden take-off when I accelerate. I just don't want to dump out a bunch of money again. I just had to replace the brake system last month. I don't know why this truck is not that old with so many issues. Did you ever find a fix?