Verify the connection to your idle control valve. The connectors on mine were very brittle. You can tell if the connection is good or not by disconnecting the leads to the idle control valve. If the car idles the same (high) then either the connectors/connection is bad or the unit is bad (unlikely because yours seemed to have worked before). I made new connectors by using standard crimp connectors from the electronics or auto parts store. strip the old connector off, crimo ine end, and pick a connector that, on the other end, fits nicely onto the valve