I have very annoying rattle in my left door when i play some high bass music in my mustang. I even tried shifting the balance of the speakers from left to right, but the problem still persists. Even when i play the music turning only the rear speakers on, the problem is still there. Can anyone one help me with this?

 

I have the same issue in my '03 conv.. It is both front doors. I hope someone has some help out there.