Take the throttle body off the car, look at the side that would have faced the firewall, you should see two screws holding a plate on. Unscrew them and pull the plate off. Take a couple screwdrivers and screw the plastic thing in there down, reassemble and see if that fixes the reving problem. I think you have an air bubble as well which is causing the thing to overheat, you'll have to try and get it out or take it to a shop that has a special tool for getting them out. Just to let you know the air idle control valve is on the front of the intake manifold and has a coolant line running to it, if this is the problem its cause of the air bubble.