1995 Z28 stock M6

I've got a buzzing/rattling sound that recently developed which seems to come from the windshield wiper area on both sides of the dash. When the car is at idle (800 rpm), the buzzing is rather loud in the cockpit. Bump the rpm up to 1200, and the sound stops completely. let the rpm drop back to 800, buzzing starts again. temperature of the car and weather conditions make no difference...always buzzes below 1200 rpm Unless the windshield wipers are on. if i turn the wipers on and they pause due to wiper delay, the sound is still gone. turn the wipers off, and they buzzing starts again when the wipers return home. outside the car with the hood up, it is barely audible, until you put your ear close to the plastic vent area between the hood and glass...haven't had a chance to rip the dash/wiper assembly apart...i have fiddled with the wipers and the wiper arms, and that doesn't seem to make it stop. anyone else have this prob? i've heard it in only one other Z28...a 97, i believe.

thanks all...

Travis

 

i know it's a goofy question, but somebody has had this happen before...

travis