I have a 2001 F150 4x4, and the seat in it seems loose. When I'm driving and start to slow down and or go over a large bump you can hear the seat pop and move. I've taken it to ford and they said they tightened it down and it still does it. The dealer here in town said they have had two other trucks that have had the same problem and they can't figure out what to do. They said they've replaced the tracks and what not and still don't know what to do. Does anyone have any idea what I can do??