Take the IAC valve off so you can see the valve.
Connect its wires
Turn key on, valve should open all the way
Remove wires, valve should close all the way
When you turn on the key with fuel injected engines, the IAC valve opens all the way for starting, that's why when engine starts RPMs go up to 1,500+ normally, then computer starts closing IAC to set cold idle, 1,100, or warm idle 700
This is not a Ford thing, all fuel injected engines use an IAC Valve and are programmed similar to this.
IAC Valves use Step or Stepper Motors, these can be turned to a specific "step", there are over 100 "steps" the computer can call up, so computer might call up "step" 100 to open valve all the way, and "step" 30 for warm idle.
This "step" part could fail, so OHMs are correct for an electric motor but "steps" are not working
Last edited by RonD; 05-20-2015 at 07:57 PM.