Answer
Ok, but how high does it rev? is it all the time? only when cold? a vacuum leak would most likely cause the car to stumble and idle rough, not rev higher. either the throttle is sticking due to carbon deposits in the throat, or being mechanically held open by another mechanism. if you have in isc stepper motor, then remove it fro testing purposes, if you have an iac, the plunger may be hanging up and not able to close fully.