My passenger seat rattles at bit when empty. Think it rattles on the frame and perhaps the seat back is loose as well. I only notice it over a seires of rapid bumps or a very hard bump. Even so it is iritating.

Anyone have any suggestions? it seem all the bolts are tight. I have checked ot two or three times and found nothing i could adjust. I tried setting the height of the seat low or high-no difference. TIA