Engine Revs to Redline on Cold Start 6.2L

FredJ · February 21, 2021

Happened to me once, today. AT4 6.2L Wasn't exactly a super cold start, as I keep the truck in the garage. The temperature was probably around 5 deg C. I've been driving the truck for 7 months without issue. For the past few weeks its been as cold as -30 C and starting no problem.

Has there been a solution or is the dealer still investigating?

Transient · February 21, 2021

Add me to the list of people this is happening to. Occurred twice last week when I first started my truck. I'm in San Diego, and I'm stuck at home every day until at least noon because the kids are being forced to do online school by their ******* teachers. Temp outside was about 60°f+ on both days. It's not a cold weather issue if it's happening to me. I drove my truck almost daily, mix of highway and city driving. I have a 2020 Trail Boss LT w/ 6.2.

Sent from my SM-N960U using Tapatalk

Denny NWO · February 21, 2021

It's been a week with the monitor connected to the OBDII and connected live with GM TAC and my truck has not revved to 3500RPM but has coughed and fluttered upon starting but it recovers immediately. I was told to not mark the event until it revs. The Polar Vortex brought the temperature here to -30 to -38 without the wind chill and i think the colder weather doesn't amplify the issue. Temps are back to normal but after reading Transients post from San Diego, I guess temperature is not the issue. I know a co-worker with a 6.2L AT4 always starts his truck with his remote and didn't realize his truck had the same issue until he went outside to listen to it start with the remote. GM knows it's only happening to the 6.2L engine, there are now 7 in my area with the same issue according to my dealer. I will let everyone know once the issue is identified.

Steve-2019 · March 14, 2021

@Denny NWO Any further update on this issue?

Denny NWO · March 15, 2021

On 3/14/2021 at 3:29 PM, Steve-2019 said:

@Denny NWO Any further update on this issue?

It stopped acting up. sometimes flutters on start up and immediately recovers but it has not high revved since the second live data logger was installed.

redwngr · March 16, 2021

1 hour ago, Denny NWO said:

It stopped acting up. sometimes flutters on start up and immediately recovers but it has not high revved since the second live data logger was installed.

Sorta good news/bad news.

I was hoping you were going to tell us that an issue had been identified and corrected.....

Transient · March 16, 2021

Sorta good news/bad news.
I was hoping you were going to tell us that an issue had been identified and corrected.....

It's GM. They have no problem identifying an issue, but don't come up with solutions. Just look at AFM. They kept it on the market for 15 years. I've been burned by GM on AFM. Literally left me stranded in the middle of Wyoming when the bottom end of my 2007 Tahoe's engine went to poop. I was under the warranty mileage limit. $10,000 negative equity rolled into a Chevy Malibu just so I could get my wife home and not have her in trouble with her command. To make matters worse, we were returning from a trip that was solely made for a funeral. Imo, when it comes to problems with vehicles it is best to fix them yourself. That's the only way you can be sure it's fixed.

Sent from my SM-N960U using Tapatalk

Denny NWO · June 19, 2021

My truck hasn't acted up since January and not at all with the GM live data logger so I returned to the dealer at the end of March and they removed it. The service manager said all the others that were having issues stopped at the same time as mine. He thinks it was a fuel issue, they switch between summer and winter gas up here. Will have to wait and see what happens in the fall.