I had this rattling plastic noise over certain bumps forever. Took a bunch of things interior apart, couldn't find it. Noticed if I hit the roof liner near the sunroof it produced that same vibrating noise. Inspected the sunroof, and found that with the liner closed, noise was lessened a lot.

Did some more digging, took of the driver's side rear passenger door weatherstrip, took the dome light down and the two clips holding the headliner up, and squeezed it down just enough to see a WHOLE LAG BOLT incredibly lose (like 3-4" out of where it shoud be). I guess bumps over many years....the bolt was holding the back of the sunroof/ liner track in place. Got a small wrench in there, tightened it up, and no further sounds. FINALLY!

Word to the wise...the UPPER half of the roof liner is fibreglass....my wrists found that out the hard way. Wear gloves.

 

AWESOME! I will look into my noise with that in mind.