The idle air control (IAC) on the Ford Sport Trac controls the idle speed of the engine by allowing air to bypass the throttle plate. It works much the same way as a choke on older engine systems and is located on the side of the throttle body. You can check the functioning of the IAC with an onboard diagnostic (OBD) code reader or, in the absence of a code reader, by measuring the ohms between the test pins on the valve. The resistance should read 7 to 13 ohms.
Unplug the wiring harness connector by pressing in on the plastic tabs and pulling the plug out.
Remove the two retaining bolts on the IAC valve's body. Lift the IAC off the throttle body. If there is a gasket, make sure all gasket material has been removed.
Center the gasket (if applicable) over the mounting IAC mounting surface. Insert the new IAC into the cavity. Install the retaining bolts and tighten them firmly. Reconnect the wiring harness plug.
