I recently noticed that I get this anonying sound when crusing at low RPMs. I'm almost positive that it's a loose heat shield because this same thing happened on another ford I owned and it sounds that same. I looked under the car and chouldn't locate the damn shield for the life of me. A buddy of mine told me that it might be in the exaust system and that I might have to take it apart . So my question to you guys is where is the heat shield located and what do I need to do to get at it and fix it. I'm assuming all I need are some screws or what not, but if anyone has done this before I'd love to hear what you have to say.