rumble/rattling noise at idle

hey guys, new to the site and the GTP. i just picked up a 98 with 95k miles from the original owner . car is awesome and runs great but i got a question, when idling it makes a weird noise like something is rumbling/rattling around under the hood, kinda hard to pinpoint and you can only hear it when idling in D really, if you gas it to about 1k rpm's the noise is gone, i tried doing a few searches on here and some that i read that sound similiar are to replace the supercharger coupler, what part of the SC is that exactly? any write up or pics on this? any other ideas would be appreciated.. thanks!

Here

That is a darn nice how to..Hit the nail on the head.

nice... thanks!