Stock leather seat PROBLEM!! HElp

My truck has the stock leather bucket seats and I am having a problem with the passenger side seat. Whenever someone is sitting in the seat, when coming to a stop and then accelerating again, the backrest of the seat has about 1 inch of play. I have sat in the seat with someone else driving and it is really annoying, you get jerked back and forth. I took the seat out and cannot find where the adjustment is or how to tighten it up. It does feel somewhat "spring loaded though" whereas if you push back on the seat and let go, it will return to it's posistion. Anyone have thoughts or have this same problem???