Hesitation while driving

[namawon]

I recently picked up a 89' two tone coupe(picture below)
and when cruising at a constant speed it hesitates and bumps. It accelerates and decelerates fine.
I cant figure it out. Any help is appreciated.
Whats been replaced:
spark plugs
plug wires
distributor cap&rotor
ignition coil
TPS sensor
fuel pump
injectors