I've been searching for about 20 minutes for "rattling underneath," since I've got a similar problem with my '96 at the moment, and I'm pretty sure this is the problem! I think it might've been when I bottomed-out like a son-of-a-gun on a GIANT speed bump a few weeks back.
I only notice it between about 1700-2200 RPM, and only AFTER I let off the gas in P or N. Driving noise probably covers it up too much to notice when I'm movin' about.
Thanks SO much for this info, it's been driving me nuts. Hopefully I can talk my boss into letting me use the car-lift in my shop for personal use
