Sounds like a family of squirrels under the hood!
My 97 SE has a high pitched squeaky chittering sound coming from the engine, it makes it only when the engine is idling. It has nothing to do with vehicle speed, it does it if the car is sitting still or doing 65 MPH so long as I'm not pressing the gas pedal. It sounds a bit like when old cars had a loose V belt, but of course our Bonnies have a serpentine belt. I'm guessing it'* a bushing in one of the pulleys. I'll probably just drop it off at my dealer and let them figure it out, but I thought I'd ask if anybody has knowledge of a common cause, or if these squirrel noises are kind of random in cause.
97 SE, teflon wiper blades, Dunlop Sport A-2 tires, Leather steering wheel cover, Pioneer DEH-P480MP mp3 CDRW head unit, Pioneer 12-disc changer, iPod hookup, Boston Acoustic 3 way 6x9'*, Boston acoustic separates in door pods, Alpine 4 channel amp in trunk. Magnaflow dual outlet muffler and Ractive stainless tips. Autozone rice pipe and K&N 4750 intake kit. Clear corner lights. Energy Suspension end links.