help needed, 94 buick century wagon

so a month ago, i had rack and pinon steering replaced.

no problems.

two days ago, im driving, and im feelign a vibration in the pedals, wheels, and dash.


it only happends after ive excelorated to the speed im happy with. when i back off the pdeal to cruise, and say i hit the gas to pass someone, it happends when i hit the gas. everything shudders.

if i take my foot all the way off the pedal, and apply it again, its ok.


it happends big time at 60-65, but after i had it put ona dyno, and the guy said the plugs and cables were bad. i replaced them all. went for a drive, and it is still doing this. now it happends when im going slow as well. but only happens, when i let me foot of a bit, then apply pressure to the gas again.


anyone have this problem, or possibly help me with a solution?

well i replaced the motor mounts, no difference.


i had the mechanic in the car, and offcourse, it had no problems, so i told him to keep it till its fixed.