the passenger window in my 99 gt will roll down, but it won't roll back up, it will go down part way and then go back up, but to get it to go back up from the bottom, i have to slam the door...
also, is the white plastic film important, can i just rip it off the door and throw it away?
WD-40 is your friend. The white plastic cover is just a moisture shield to keep moisture in the door, it can be removed if you want. Spray wd-40 in the track mechanism and it will take some of the stress off the motor. It is probably the motor or the connections to it, once your door panel is off, it will be easy to see. Since it still goes up, I doubt its the regulator.