if im not mistaken..it is behind the timing cover..it runs off the timing belt You are correct. It is the belt tensioner for your timing belt and a pain to release to release the tension and also not the easiest to replace.
Front of engine (behind serpentine belt).
Mine did this and I found out it was the timing belt that needed to be changed.
After you have released the tension from the belt, remove the 2 obvious bolts that hold it to the engine block.
It has a Timing Belt.
Timing belt replacement is a pretty big job. I'd go to the parts store and pick up a Chilton or Haynes manual.
its under the black cover behind the serpentine belt
The 1991 Lexus ls400 has a timing belt.
It does not have a timing belt, it has a timing chain that requires no maintenance.
No Belt=It has a Timing Chain.=
Pontiac Grand Prix does not have a timing belt. It has a timing chain and it is replaced when it breaks.
The 2004 2.0 liter Pontiac Grand Am does not have a timing belt, but instead has a timing chain which requires no maintenance.