The idle air control valve (usually referred to as the IAC valve) is an important part of your engine. The valve regulates the average rotation of your engine at idle. If your IAC valve is faulty, you may experience irregular idling (lower or higher than normal). Sometimes this can cause your engine to misfire. The Jeep Liberty is normally equipped with a 3.7 liter V-6 engine. This tutorial is specific to the 3.7 liter engine, although the 2.4 liter I-4 should be similar.
Open the hood and locate the idle air control (IAC) valve. On both the 3.7 liter and 2.4 liter engine, it is located in the rear center of the engine bay. The valve is mounted on the side of the throttle body.
Use the pliers to unhook the negative (black) battery cable. Pull the cable away from the terminal for safety.
Press the black tab on the electrical connection attached to the IAC valve. Pull the connection away from the valve.
Remove the two bolt-screws mounting the valve to the throttle body. Use a Phillips screwdriver or a standard socket wrench.
Lift the old valve out, and set it aside. Attach the new valve and replace the two bolt-screws. Tighten them well.
Replace the electrical connection. Reattach the negative battery cable and start your engine. The engine will take a few cycles to reset and relearn the proper idle speed.
