Have your car scanned for codes. Several auto parts stores will do this for free. Post the codes here for further assistance.
In the meantime, try cleaning the throttle body. Use throttle body cleaner and a small brush (like an old toothbrush) [don't use a brush with wire bristles]. Often a dirty throttle plates will cause a high idle.
One more thing, are you sure that the new IAC had a O-ring on it. I've seen some techs leave this ring off by accident and it causes crazy idle problems. Also remove the IAC and clean its' port.
Saturday, December 7th, 2013 AT 11:05 AM