Hi all, I'm newbie here. I have a 93 Altima w/2.4L and 117k. It runs pretty well, but at a warm idle I can hear a clicking sound coming from the engine. Anyways, I took the valve cover off and noticed excess play in the timing chain- about 1.5"-2.0" This could also be the cause of my fluctuating idle, I dunno...Do these need to be replaced or is there a tensioner that can be adjusted or replaced? I've read previous posts on the altima timing chains and have the impression that the timing chains dont need replacing??? What is involved in such a repair? THANKS!!!