There are several things that can cause your engine to idle high. The most common is a sticky throttle plate. Get a can of carb cleaner and clean out the throttle body. If the problem still exists check all of your vacumn lines for leaks. Your ignition timing can also affect your idle speed as well (though it normally sends it down not up). If you check all of these and still dont get anywhere you can turn down the idle by backing off the idle screw.
When I first installed my Injen CAI
the same thing happened to me...my idle went from 700-750 up to 1000-1500...So I just turned my idle screw to adjust my idle (if your not a mechanic I recommend getting help.)