RICK323

I'm really puzzled by a persistent problem with bucking at 40 to 45 MPH, especially when going at constant speed. If accelerating, it smooths out, or if you drop out of overdrive, the additional rpm's seem to smooth it out also. New fuel filter, fuel pump and computer installed first and a cleaning regimen performed on the injectors. Then new spark coils, caps and rotors. The mechanic says he tested the mass flow sensor and it's OK, so he thinks it's "the computer". Has anyone had this problem? The car has 145K and has run smoothly and well since we bought it over 5 years ago until just recently.

SOMEONE HELP PLEASE!!!!! I just bought a 92 sc400, and im having that same problem when Im cruising between the speeds of 40 - 60mph and let off the accelerator im getting that hesitation and when i resume accelerating im getting a clunk. Anything under 40 mph its fine. What could it be?