Things you should do:
Test your FITV. To do this:
1. Remove your intake pipe from your throttle body.
2. Start your car.
3. Cover the small hole in your throttle body. It should have suction. If not, replace your FITV.
4. Let your car warm up to opperating temp. Let your fan kick on at least two times.
5. Cover the small hole in your throttle body again. Now it should not have any suction. If it does, replace your FITV. This part is about $50
Check for vacuum leaks. This picture shows the vacuum line you should check. Check by spraying them with soapy water, and look for bubbles. Also spray the throttle body to see if the gasket is leaking.
Clean your IACV (same thing as EACV, IAC) with carb or brake cleaner. You may also need to replace this. I'm not quite sure how to check it. One way I think you can check it is disconnect the 2P connector to it while the car is idleing. The RPM's should drop quite a bit. It is a semi-expensive part (about $130).
Replace your PCV valve. It's only a couple of bucks from your local auto parts store.