My 08 DE, with all stock sound system, has a loud rattling, almost more of a buzzing, in the passenger side door panel. I've spent some time sizing it up and it seems to be coming from the button that rolls the window, but I don't for sure. I thought some dirt or something may be caught in a tight space so I lightly tapped the door panel all around, especially near the button. It stopped for a days or so but has since come back. I've learned that it isn't the speaker becasue it buzzes over bumps wit hthe stereo turned off, although it also buzzes with a lot oo bass. Sounds like a damaged speaker but I know it isn't. I don't want to remove the door panel unless I have to. Any ideas? Thanks.

 

Its actually quite easy to remove the door panel... For the front, 3 screws and then just carefully pop the panel out... Its held in by plastic clips (very much like Lego)... That would be the best way to see if there is anything loose inside...

There's a video on youtube that shows you how to do it (search on "lancer door panel removal")... The guy there takes less than 5 minutes to do it...

 

Also take your car to get the door / window screws fixed. I think there is a service notice for this somewhere here. The screws that hold the window in place come loose over time due to improper torque specifications. This might help and you could mention your other problem to its all covered under warranty.