I have a 2000 SE 5 speed. Bought it at 37k last November and for as long as I can remember I've had a rattle. Instead of trying to explain it i'll post what somebody else posted 3 years ago on another forum (I used google!) but they never found a reply. My problem is the exact same. They said:

"My 2000 GXE automatic has had this problem
essentially since I bought it: when the car is
accelerating and is revving at about 3000 RPM and
up, something in the front of the car makes a
clicking or rattling noise. It sounds kinda like
baseball cards in a kid's bike spokes.

I originally figured I had a branch stuck in the
underpinnings dragging along, but no such luck.
It happens more frequently when the engine is
cool, though I heard it a few times during a road
trip a few months back. It used to happen only
at about 3100 RPM, but it's started becoming less
selective recently--I've noticed the sound below
3k RPM and into the 4-5k range. It is most
prominent when I first pull out onto the highway,
though I've yet to hear the sound below about 20
MPH.

I've taken the car to the dealer twice, and it's
refused to make the sound either time. I'm
leaving the car overnight on Tuesday to see if
maybe it'll show up (The dealer is about 30 miles
away, and I figure the engine is too warm to do
it frequently after I drive out there). However,
the mechanics seem to be totally stumped, so I
was hoping someone on this forum could be of some
assistance. Thanks,"

If anybody has encountered this please let me know Thank you so much!