The passenger side window on my 1999 Z3 2.8L coupe, is very slow to roll down, but goes up just fine, the driver side however rolls up/down about 3-6 inches before the motor stalls out, unless the door is open. When the door is open the window works great, I have tried to figure out if there is any certain angle at which this issue crops up, but it seems to be inconsistent, sometimes working until the door is fully closed, and sometimes it starts slowing down when the door is just close to the car body. This inconsisancy makes me suspect the wiring and/or connections, however I have tried operating the wondow while at the same time pinching, twisting and rolling the wires in my hand and the problem still doesn't show up until the door closes. I also checked the motor, but it isn't loose at all. I don't know if its related but after playing around with the window for a while the auto up feature on the window will stop working, until I go out the next day and it works for a while until the motor stalls out a time or two and then to get the window up all the way I have to hold the button down. Oh and the passenger side window is slow in every position, not just when the door is closed. Does anyone have any suggestions?