I think I solved the problem with my vehicle. The window seal itself seems to cause some problems for me. I've noticed this because with the window up/down it flexes the seal in different ways. My rattle always went away when I just cracked the window. What I did was rolled the window down, pulled the corner near the top away from the door and added some 3m strip caulk about 4inches down, around the bend and then 2-3 inches along the top. Fold the seal back over and pinch it to stick it all together. I also added a small dot behind the rubber square piece ikxdf added a foam piece onto but don't think that did anything as it wasnt contacting anything on my vehicle. Going to try this on the passenger door as I hear the same thing over there.