It's probably binding. If the motor is working, ie. moving the window at all, then, that component is not the problem. It may not have all of it's original gusto, but it's at least working. Tug on the top of the window when it's halfway up and see if it has any excessive play. If so, then it's binding in the channels and will need to be cleaned and aligned. This is a task that can require considerable mechanical aptitude and patience. Give it a shot if you feel comfortable with the challenge. You may be better off replacing the whole mess with a used motor/regulator. No idea on price. Check with the Parts Shop here. Lee might be able to find the goodies for you. You seem to be having a multitude of problems with this car. Good luck.
1987 BMW 325
[This message has been edited by jeffsr (edited 06-28-2000).]