When you turn the steering wheel, you place a load on the engine, on the power steering line is a power steering switch, This informs the ECM to increase the IAC (idle air control). You may have a problem with the IAC valve, but the sure way to do it is with a scan tool that does Ford key on engine running test.
March, 12, 2013 AT 1:15 PM
I agree I would suspect either the power steering pressure switch or an issue with the idle air control valve.
March, 12, 2013 AT 1:24 PM
Try cleaning the throttle plate on both sides with choke cleaenr and iac hole first