What the heck happened to my truck's seat? I was driving and all the sudden the seat started acting like a ballon deflating. I sank several inches with out hearing anything snapping or breaking. Now the center section of the driver's seat is all sagged out and absolutely uncomfortable. C'mon I weight 165 soaking wet. This should be happening! I have searched around a little for a replacement but am not seeing any so far. This is a plain ol manual vinyl covered model in tan. What holds up the seat cushion? Thanks for looking and any help would be great.