Good afternoon everyone.

i have a 2020 Colorado ZR2 with 56000 miles. It has i've been stuttering, almost like driving over a rumble strip, sometimes a light buck. If I accelerate it seems to go away. I do notice a slight surge in rpm but it's not much, maybe 250. The problem has gotten progressively worse though.


I tried to take it into a shop but they told me they charge a $175 diagnostic fee and $50 to work with extended warranty. I'm just trying to figure out what to do, who to take it to and how much the fix would cost.