I know this sounds crazy but really check your tensioner pulley. I have seen this on atleast 4 contours zetecs 2.0L. look at the serpintine belt near the bottom while the car is in gear and running if its jumping around you'll need to replace it. Oh by the way be careful and dont get ran over have some one help you. the tensioner pulley housing cracks and causes the belt to jump around make noise and idle bad.. i had this problem on my car.
