1997 Pontiac Grand Am • 115,000 miles

This problem started with the idle at 4,000rpm. I replaced the throttle control sensor which made no difference. I removed the throttle body, cleaned it out with carb cleaner, especially where the IAC comes in (I think that is where the main problem was). I checked vacuum lines. I replaced the gasket, changed the spark plugs, wires, air filter, and oil, but it is still idling from between 1,000 - 1,600. How do I get it to idle at 800rpm? Is there something else I can do. The check engine light is on, when it goes through the test, it pretty much says there is an issue, but not specific. Where should I look next? If there is a vaccum line that would most directly impact this, which one would it be? Thanks for your help guys!
May 8, 2012.

You need to check all vacuum hoses for leakage and also clean out IACV and see what happens

May 8, 2012.
When the engine is still cold, spray water on the intake manifold gasket(s) and vacuum hoses. Watch for any place where it gets sucked in or where it makes the engine slow down momentarily. You can also pinch off various vacuum hoses to see if one brings the idle speed down. If you find one, follow it to its branches, then pinch each one to follow it to the leak.

May 8, 2012.