2025 Tahoe RST Misfire Cylinder 7 - Service ESC & Traction Control Lights (Intermittent Issue)

[Alazemi Salem]

Hi everyone,


I’m facing a frustrating intermittent issue with my brand new 2025 Tahoe RST (around 5,600 miles / 9,000 km on the odometer).


Symptoms:


When the car is cold, it runs perfectly fine with no issues or lights.


After driving for about 8 to 10 minutes and once the engine gets hot, the car starts to idle rough and shake (noticeable misfire/stumble).


Immediately, the dash lights up with: Service ESC, Service Traction Control, and the Check Engine Light.


Dealer Diagnostic:


I took it to the dealership, and the scanner pulled a misfire code for Cylinder 7.


The technician claimed it was just a loose spark plug/coil wire, "re-seated" it, and cleared the codes.


Less than an hour later, as soon as the engine warmed up again, the exact same issue came back.


Since it only happens when the engine is hot, I suspect it’s a faulty component failing under heat rather than just a loose wire. Has anyone with a 2025 model experienced this? Was it a bad ignition coil, a faulty fuel injector, or a wiring harness issue on Cylinder 7?


Any advice or GM service bulletin numbers would be highly appreciated before I head back to the dealer tomorrow!

 

[GMCnewbee]

My vote would be for a defective component. Electrical devices have either a quick failure or a long life. I say "back to the Dealer" or try another Dealer.

 

[blanchard7684]

Bad spark plug ( porcelain cracked), ignition coil, or boot.

Hopefully not anything with the intake or exhaust valve or head gasket, that happens with heat input.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please. If we can't see it, it does not exist.

You are already receiving sage advice from the knowledgeable folks on this Forum.

It would also be helpful if you posted that actual trouble codes that are triggering the dash warnings. The Dealer must have observed them.