Both the seat backs on my 02 S are not latching. I lean back and the seat back goes back 2 to 3 inches and wondered if there's a way to tighten up the seat backs so they don't move. I've tried all reclining positions and there's 2 to 3 inches of play in each position.

 

I'd suspect that the latch mechanism that locks into each recline position is damaged or worn. Were you in an accident? I do not know how to repair this besides prying off the covers of the levers. The mechanism is probably deep within the seat, so you may be out of luck.