Get out the CD manual and start taking things apart. Sounds like you may already have something amiss in the roof. Mine did that and then one day the passenger side would not go down at all. $400 worth of parts later, I had the factory mods installed and the roof adjusted. I had broken the right side lifting arm. Daughters car has similar problem. Will do the work on hers in the spring. Doesn't hust to clean and grease the rails and replace any of the little pads that ride on the rails that have fallen off (they split and fall off). BTW, most folks I have heard of with sunroof problems reported the passenger side was giving them trouble. Your driver side problem is the first I have heard of. PS: buy the little plastic clip sets that hold the inside panel to the roof. I didn't and regret it.