Slowly gaining acceptance
The driver's window has gone up and down slower than the other windows since I've had the car, and I've been meaning to pull the door panel to lube the track and mechanism. The other day I had this black streak appear on the window when I closed it. It was sticky, like adhesive or butyl tape. I was able to clean it off with WD-40, but it started appearing again when I opened and closed the window. I'm assuming that this is contributing to the slow window, but what might it be?