ok, i have a '98 GSR and over the last month it has started making a noise somewhere near the hatch. it sounds like its coming from the glass somewhere, but its kinda hard to tell as only happens when im driving. its definetly coming from somewhere near the rear-passenger side. it also certainly sounds like a metal on metal or a metal on glass type vibration. when it is just a slight vibraration it just sounds like a relay clicking on and off. and don't tell me too unscrew the rubber thingies on the hatch , cause i know about that and tried it. one person who rode in the baack seat sid it sounded like it was coming from behind one the panels, and if you let the back seats down it gets a little bit louder so it might be frm the trunk area
it is the worst when you let off of the gas and use the engine for braking. i don't think it has anything to do woth the rear wiper either as turning it on has no effect on the sound. please help, it is driving me crazy !!

 

bump....

sorry that post was kinda sloppy, i was kinda drunk. but the noise is still there. its really hard to nail down cause i only hear when i go 70+.

 

Try wrapping electrical tape around the metal trunk latch loop