I feel like I'm going crazy when I drive mine. 2021 5.3 Trail Boss, build date 7/21, 1,700 miles, bought just over a month ago. I swear I feel constant misfires when holding speed on the highway or going up a long slight grade. It's not pronounced at all, I don't think a passenger would even notice, almost just feels like tiny constant bumps in the road. Maybe all in my head from reading this forum too much? RPMs between 1100 and 1400. I drive the same roads every day, and I swear I didn't feel this for the first 1,500 miles. Not sure if it's misfires, or if the truck is going into 10th gear when it really shouldn't be and bogging down?