I've read up quite a bit on this one but am still having a problem. In my high idle search I found my FITV port inside my TB has tons of suction when warm. I replaced the FITV with a new one, tightened it, and have the same issue. I got a used IACV and it still does the same thing. I don't have much suction through the top port in the TB at hot or cold idle because my idle screw is tightened to try to get my idle down. If I cover the bottom port in the TB and back out the idle screw with the IACV unplugged, it idles well.
I have a new FITV and have gone as far as testing the thermostat inside and know it works as it should. I am concerned with the IACV because it seems to buzz constantly with the ignition on. It can be heard when the snorkel tube is taken off of the TB and the ignition is "ON" with the engine not running. When disconnected the buzzing stops. I don't know if that is normal or not. I also don't know if the IACV would affect the port in the TB for the FITV causing air to pass when warm??? Would the TPS affect that?