If its a new IAC, then be sure you installed a valve-closed model, not the standard aftermarket model which has the valve open. 90% of aftermarket units are valve open and are made by Borg Warner, are not usable on the SC and will cause the idle to race. I got my replacement from Ford, but I've heard that Advance or Carquest or someplace like that has the right ones.tbirdboy said:Checked all vacuum lies, IAC has been replaced and tubes are sealed. What hell is going on? This **** is driving me crazy!