2021 AT4 with 6.2l and I also have the shimmey and vibrations when idling. I have 40,000 miles on it and it has done it since I purchase it a year ago. Got extended warranty and everything and yes, no codes = no service apparently. I can’t understand how they can turn them away knowing something isn’t as advertised. I feel like GM needs to write this as a disclaimer on the sticker
Attn: most likely to shake and vibrate when new, but it’s perfectly fine and still charge $70,000 for the truck and see what sales look like. Love my truck. This is the 2nd GMC truck I’ve owned and I’ve had the dynamic fuel managemEnt turned off since I bought it. I def feel like it’s the motor mounts yet they won’t throw a code. Tough to force a dealer to honor their “Certified” bumper to bumper when there is no code for them. It’s BS is what it is.
