Note that the 5.4L V-8 only used an IAC valve through the 2004 model year; 2005+ model year trucks use the throttle blade in place of an IAC valve to control idle speed. All 4.6L V-8 engines (1997 to 2010) utilize an IAC valve.
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• The IAC valve is located on the driver side rear portion of the throttle body. Remove the plastic guard that covers the throttle body with a 10 mm socket.
• Locate the IAC valve and remove the wiring harness.
• Remove the (2) bolts securing the IAC valve in place with an 8 mm socket, then gently lift the IAC from its mount. Remove any remnants of the old gasket without dropping debris into the intake.
• If necessary, carefully clean the surface of any gasket material that may have stuck to the mounting flange. A shop vac can be used to prevent small pieces of gasket material from falling into the tubes of the mounting flange.
• Once the mounting surface is clean, install the new gasket and IAC valve (reverse removal). Place a small amount of anti-seize compound on the tip of the mounting bolts. The bolts are coated, so corrosion isn't a huge concern. However, the anti-seize will act as a lubricant and prevent the hard steel bolts from cross threading into the soft aluminum flange.
• Tighten the (2) bolts that hold down the IAC, being careful not to overtighten as the aluminum threads can become damaged easily. Reconnect the wiring harness and reinstall the plastic cover to complete the IAC valve replacement.
• Comparison of the new and old IAC valves. In some instances, buildup in the valve causes it to malfunction or respond slowly, while in other instances the actuator itself stops working. If the motor still works, clean the valve and keep it as a spare.