I'm having the same problem with my '02 WRXat the driver's side window. All other windows seem to power up & down fine. The first time it happened, I found it to be that a bolt had come lose that holds part of the window lowering mechanism in place. The other bolts were lose as well but hadn't fallen out yet. After I replaced the missing bolt, the window began to work again correctly. It's been a few months. However just today, it stopped working again. This time however, all the bolts are still nice and tight? I plan on removing more when I get some time. I'm wondering if the electric motor has failed. I hope not. But, that is a possibility.