Originally Posted by kreeghor
It only does it in drive, reverse and not in neutral or park. ... It will jump from about 1200 to 700ish rpm when the rattle starts.
Did you post that correctly - it goes from 1200 rpm down to
700 rpm when in drive or reverse? That's odd my '97 idles at about 700 rpm (or a little lower) when in driver/reverse. Idle at neutral is at 8-900.
Also, don't forget to check you engine mounts. Best way - see if you have excessive engine tippings when going into drive/reverse. That will put pressure on all sorts of parts to make noise. Had my '97 done at 90K miles. I think they were pretty common problem on this generation.
If you get stuck and cannot find the problem, repost and I can measure my tipping distance on my '97.