Sunday, February 2nd, 2014 AT 3:18 PM
My trailblazer is driving me nuts! The trailblazer seems to be missing at around 50 55. The car shacks and then will smooth out. I have flushed and changed transmission filter. Flushed and changed diff fluid. Also cleaned throttle body changed air filter when I was getting a p0171 code. Reset check engine light after cleaning throttle body and filter. I have been driving it around for around a hour and check engine light does not come on. But still runs very rough at 55 and up a hill at 55. It's the wife's car and she has the kids most of the time don't know what else to do. Anything at this point would help.