If you have a service on your car coming up anytime soon, take it to the dealer. Last time I went there, (I have an 05 ExL btw), the salesman told me that this window stuff is something that nobody bothers to ask about when getting checked. The motor is something that eventually tends to give you problems but is often ignored. The funny part is that the check is actually free. I'd do that first just to pinpoint the problem and go from there.