Thats the Throttle Screw not the IACV, The IACV is located under your Intake Manifold, this connects to your FAST IDLE VALVE, I had the same problem you need to take off the IACV and turn the bullet on the inside down a couple of turns, also check if there is any air in your coolant, you may want to bleed out the coolant a little bit to make sure there is no air,

Also is the check engine light on, if so run the codes and let me know.