How to Clean the IAC Valve and Throttle Body on a 1992 5.0 Mustang

The Ford Mustang has a longstanding tradition of pure driving excitement, especially those equipped with V-8 engines. The 1992 Mustang came standard with a lowly 105-horsepower, 2.3-liter four-cylinder engine, but its optional 225-horsepower, 5.0-liter V-8 made up for the four-bangers shortcomings. The 1992 Stangs 5.0-liter uses a throttle body to regulate the airflow into the intake manifold, regulating the engine speed. When at idle, the idle air control valve allows a small amount of air to bypass the closed throttle body to maintain the engines idle speed. Both components get bombarded with tar, soot and other contaminants that internal combustion creates. You can clean the throttle body and IAC valve with relative ease.

Instructions

Trace the air filter outlet hose toward the engine until you reach where it connects to the engine. This connection point is the throttle body. Look on the front side of the throttle body and find the electronic components bolted to it. This is the idle air control valve.

Unplug the wiring harness from the IAC valve. Remove the two screws securing the IAC valve to the throttle body using a ratchet and socket. Pull the IAC valve and its gasket from the throttle body and discard the gasket.

Place a white, lint-free cloth on a work bench or surface, and place the IAC valve on it.

Spray throttle body cleaner into the inlet hole, the hole closest to the IAC valves electrical receptacle, with the hole facing upward to allow the cleaner to pool inside. Repeat this step on the outlet hole, which is farthest from the electrical receptacle.

Scrub inside each hole inlet and outlet with a small, soft-bristled, pipe cleaner for about 30 seconds. Carefully dump the throttle body cleaner from the holes on the far left side of the white cloth. Pay close attention to the color of the throttle boy cleaner on the cloth, this helps in telling you when the IAC valve is clean. Clean the pipe cleaner with throttle body cleaner.

Repeat steps 5 and 6, moving across the cloth each time you dump the throttle body cleaner. When the throttle body cleaner comes out of the IAC valve the same color in consecutive repetitions, the IAC valve is clean.

Place the IAC valve on the cloth with its mating surface side facing the cloth for 10 minutes to allow it to dry.

Scrape the old gasket debris from the gasket-mating surface on the IAC valve and the throttle body with a plastic gasket scraper. Wipe the debris off with a clean, lint-free cloth.

Guide the mounting bolts through their holes on the IAC valve and slide a new IAC valve gasket onto the bolts. Position the IAC valve on the throttle body and hand-thread the bolts. Tighten the bolts to between 71 and 97 inch-pounds using an inch-pound torque wrench and socket. Plug the wiring harness into the IAC valves receptacle.

Start the Mustangs engine and allow it to run until the idle stabilizes. If the idle issues remain, the IAC motor might have failed, which means you must replace the IAC valve assembly.

Loosen the hose clamp securing the air filter outlet hose to the throttle body using a flat-head screwdriver. Pull the hose from the throttle body and position it aside.

Instruct an assistant to press and hold the accelerator pedal to the floor do not attempt to hold the throttle valve open by hand or using a tool, as this may cause injury to yourself or damage to the throttle body. Observe as the throttle valve opens, exposing the throttle bodys bore.

Spray inside the throttle body with a liberal amount of throttle body cleaner. If the buildup on the throttle body is heavy, instruct your assistant to release the accelerator pedal and let the throttle body cleaner soak about five minutes, then press the accelerator pedal to the floor again.

Scrub the throttle bodys bore with a clean pipe cleaner, then wipe the diluted buildup from the throttle body with a clean, lint-free cloth. Always pull the cloth outward from the throttle body when wiping the throttle body to minimize the amount of fluid that gets into the intake manifold. Repeat this step until the throttle bodys bore is clean.

Apply one additional coat of throttle body cleaner to the throttle bodys bore and instruct your assistant to release the accelerator pedal.

Press the air filter outlet tube back onto the throttle bodys inlet and tighten its hose clamp until it is snug using a flat-head screwdriver. Let the vehicle sit for five minutes, then start the engine. Hold the engine speed at 2,500 rpm until the vehicle reaches operating temperature roughly halfway up the temperature gauge to burn off any fluid and diluted buildup that might have entered the intake manifold.

Allow the engine to idle and verify that it is idling as expected.