with my firebird, which acted the same way, it was the window motor. Cheap enough to buy, a pain in the butt to install. It goes down easy, the motor heats up because the bushings are worn, and it overheats, stopping the window rise. Wait a few minutes and try to raise and it raises a bit more, then again, overheats and stops. Look on ebay for a replacement motor, but again, on my firebird, it was a pita install.
I guess I could try that but there's no guarantee ebay motor will be better than what's on there.