I AM HAVING THIS SAME ISSUE AND USING CAPS BECAUSE IT'S DRIVING ME CRAZY!!!
my passenger dropped a TON of change in/around the passenger seat as she tried to get my change holder for paying tolls. in trying to isolate this rattle, i found like $5 hiding under there.
i suspect the bass port is the problem. i've tried taking hard right turns and using magnets to get the remaining $132,040 out of that bass port (sad effort, i know).
do i have to take the seat out to get at the bass port? is there another way? can i access it by removing the subwoofer cover on the top of the amp/sub?