There is a SS tube that goes from the throttle body after the intake tube, and it is connected with a flange with 2 hex cap screws and goes down behind the engine. Mine has developed a crack and vacuum leak, this makes the RPM go to 3000. I called the dealer and got no where, I believe it connects to the exhaust somewhere, there sounds like an exhaust leak when you drive down the road. If anyone has the GM part number and name of the part I am forever grateful! In the picture you can see the top of it, it looks corrugated.Name: 43199221.jpg Views: 4065 Size: 175.8 KB