2021 GMC Sierra Denali idle issue, downshift to stop

[Z45]

Nothing like that with mine, runs perfectly and has since new, now 9,000 miles. Never put in anything but premium 91.

[kmeleon]

2 hours ago, tootall4289 said:

It came on as I was going down a slight incline at about 50 mph.  Started flashing and then went out. 

OK, just wondering. Thanks. 

[tootall4289]

Had a fuel injector out #5.  That's fixed and check engine light is out.  Still have the vibration while coming to a stop...one problem fixed, one remains 

[kmeleon]

12 hours ago, tootall4289 said:

Had a fuel injector out #5.  That's fixed and check engine light is out.  Still have the vibration while coming to a stop...one problem fixed, one remains 

I don't think you'll get rid of that shimmy/vibration with dfm. I think they all do it. I hope someone can prove me wrong. 

Edited August 31, 2021 by kmeleon

[tootall4289]

15 hours ago, kmeleon said:

I don't think you'll get rid of that shimmy/vibration with dfm. I think they all do it. I hope someone can prove me wrong. 

Light is back on and back at the dealer...so much for hoping it was just a bad injector 

[kmeleon]

5 hours ago, tootall4289 said:

Light is back on and back at the dealer...so much for hoping it was just a bad injector 

Yeah they wanted to change my #1 injector. But I think it's a complete waste of time. Funny thing is, the last couple days I've been having trouble setting the light off. For the last couple of weeks, I've been able to do it 50-75% of the time. 

[Rcfire]

On 8/12/2021 at 9:13 AM, 603Denali said:

I too have the same problem with a 2020 Denali w/6.2.  To add to this, if I am sitting somewhere at idle for more then a minute or so, I get intermittent stumbling.  I run 93 octane so it shouldn't be the gas.  

I have the same issue.  At stop lights etc my 6.2 almost seems like it has a misfire.  It’s like it has a rough idle every now and then.  Have you had any luck figuring out what it is ? 

[tootall4289]

On 10/2/2021 at 4:27 PM, Rcfire said:

I have the same issue.  At stop lights etc my 6.2 almost seems like it has a misfire.  It’s like it has a rough idle every now and then.  Have you had any luck figuring out what it is ? 

No luck, dealer did a reprogram light was out for a week and now is back on.  Going back to the dealer tomorrow.