87 Firebird wiper malfunction

My nephew has an 87 Pontiac Firebird GTA and the wiper has a peculiar problem. The wiper comes up a little and then goes back down. It keeps repeating this unless you pull up on the bar that is connected to the crank. Then it works like it should. Any thoughts. He replaced the motor assembly aND IT STILL DOES THE SAME.

There is likely a problem with the wiper motor pulse board, also known as the wiper motor cover. It contains the contacts for parking the wipers in the "rest" position for intermittent operation, and if this cover is not installed correctly on the replacement wiper motor or the contacts in the cover are damaged, the symptom you described can occur.

If that's the case, the initial problem may have been mis-diagnosed and the wiper motor itself may not have needed replacement.

The contacts can be repaired or resoldered to the board if they break loose, or the board can be replaced - IF you can find one.