On a 1994 Ford F-150 with a 4.6L engine, the Idle Air Control (IAC) valve is located on the
throttle body. It's a small, usually rectangular, electrical component mounted directly to the throttle body itself. You'll likely find it on the side of the throttle body, near where the intake manifold connects. It will have a wiring harness plugged into it.
Because it's integrated into the throttle body, you may need to visually inspect the entire throttle body to locate it. A picture of a 4.6L throttle body with the IAC valve would be helpful for positive identification, but a repair manual or online diagrams specific to your truck year and engine would be the best resource for accurate location.
