Ok, seriously it sounds like the aliens that are communicating with each other over the baby monitors in Signs with Mel Gibson. When I first start up and nothing on. ie AC or Heat, or Radio. I get theses chirps. It cease pretty quickly, as in less than a mile. Not really a knock or a squeak and really does sound like in the movie when the kid is on top of the car. Anyone have an earthly idea as to what I might be hearing? lmao Oh, vehicle is a 95 Tacoma 4cyl 2x4 Extended Cab