Hey my car is idling up and down. It will run ok when you first turn it on but after about a minute or two it will start the idling. I have replaced the iacv and checked all the hoses, coolant is good as well. It will also do it in drive while i have my foot on the break, sometimes it will start to idle up and down then it will stop doing it again. It runs good other than that. Any help would be greatly appreciated. Thanks

 

air pocket in the cooling system. could also be FITV

 

^ yup.

When car is cold take the radiator cap off, start it and add to the coolant as the car warms up to try and help air bubbles.
Otherwise you have to clean the FITV, or just delete it if you find it unnecessary.

 

Clasic failure of IAC (Idle Air Control) Valve. please clean or replace it and problem is gone.