I have a gmc jimmy yr 2000 that I replaced the motor in. Since installing the new motor the truck bumps while going appx 55-70mph. I have replaced the air flow sensor and that did not fix the problem since it was throwing a code for it. I have had my mechanic check it twice and it is still doing it and he can't seem to find the problem. It almost feels like I am hitting a small speed bump while driving 55+ mph. Any help would be appreciated.
Tuesday, March 19th, 2013 AT 3:11 PM