So I am seeing the same issue with a 2023 Yukon Denali xl. Have had it into 3 dealers, 5 visits in total. Last dealer swapped the valve body, but I’m still having issues. I notice the vibration / shudder when maintaining speed 30 mph and up. When I am in the accelerator it’s not present, but again, if I am just maintaining speed, and you see the rpm in the 12-1500 range, you can expect it will be vibrating. Has anyone had any success? I’m considering hiring legal for a lemon. Can’t pay ultimate prices for this BS