Drivetrain feels like it’s binding under load with a bad vibration.

What is your question?

It has a significant vibration at about 1500 rpm and when under harder acceleration has a binding feeling in the drivetrain. It also feels like the pedal assembly moves when the anti skid feature is on. I have rebuilt the transmission and rear end as well as new one piece driveshaft new motor and transmission mounts. New bushings and shocks on all 4 wheels. Harmonic balancer has been checked out and is good. I have had this issue prior to changing all this stuff and it is still there so I am running out of things to try. Also completely new tune up plugs wires coils throttle body cleaning and mass air sensor. New air cleaner fuel injection cleaning has been done. Any ideas would be much appreciated.

What makes this problem better or worse?

Haven’t really found something to make it better yet.

How long has your 2004 Pontiac GTO had this problem?

Sine I bought the car.