2002 Mazda Tribute high idle problem

I have a 2002 v6 mazda tribute that as the suv. Warms up it takes longer to come down to an idle. It's not the throttle plate because on occasion it will start revving higher and higher and the throttle plate is against the adj. Screw. This vehicle has only 85 thousand miles with no play or carbon on the throttle shaft. I made a restrictor plate out of gasket matl. For the idle air control valve and where the two rectangular cavities are I punched qty.2 1/8" dia. Holes restricting the flow. The car idles and runs fine now. I realize this must be repaired correctly but the vehicle is much safer to drive now. I noticed that when the key is turned to the on position the idle air control valve does not close but you can feel a click inside of it. When removed from the airhorn. My 2005 freestar iacv. Does close when the key is turned on. I think the vehicle needs a new iacv. Hopefully this will help someone trying to figure this annoying problem out. Thanks joe