I have a 99 Grand Prix GTP with 90k miles. The car has been making this weird noise for awhile now, its kind of a high pitch whine noise that doesn't sound too different from the normal whine of the supercharger or similar to the noise a power steering pump makes when its low on fluid. The noise is MOST noticable at idle and is definitely coming from the passenger side of the engine bay near the belt area.
I finally had time to get out there and attempt to diagnose it. The noise SOUNDS like it may be coming from BELOW the supercharger, I also noticed that the tensioner pully for the supercharger MOVES a half inch or so in a way that doesn't look normal when you rev the motor and makes a grinding noise on top of the whine while its moving.
I definately think its safe to say that the tensioner is bad or atleast needs to be tightened \ adjusted, I just wondered if these things can cause a whine when they go bad.
Thanks for any input