Does your idle rise and fall over and over again? Does your ‘Stang stall when you come to a stop, or even when you put it in gear? It guess it’s time for a new IAC (idle air control, or as it’s sometimes called, idle air bypass)… or is it?
Fuel injected Mustangs use a small motor/valve assembly that allows a certain amount of air to bypass the throttle plate, entering the engine to control idle. As mileage increases dirt, air filter oil, and carbon build-up will take it’s toll and often cause idle surging and stalling. This can happen as early as 30,000 miles depending on conditions (K&N’s really speed up the process). Why replace it when you can clean it?
- 8mm or 5/16 socket and ratchet
- 1 can of throttle body cleaner
Locate the IAC Valve
- On 5.0L Fox body cars the IAC is bolted to the side of the throttle body.
- On 4.6L DOHC and SOHC engines the IAC is located on the upper intake manifold.
Removing the IAC
This part, like the rest of the steps in this article, is simple. The IAC (B) has an electrical plug that needs to be disconnected (C) Then all you have to do is remove the two 8mm-5/16″ bolts (A) that hold the IAC to the throttle body or intake. Watch out for the IAC motor to throttle body gasket, don’t lose it!
Cleaning the IAC
Next all you do is use the throttle body cleaner to clean carbon out of both of the holes (C) in the IAC valve and both of the holes in the intake/throttle body.
Putting it back together
Yet another self explanatory step. Put the IAC in place and install/tighten the 8mm bolts. Make sure you don’t forget to reinstall the gasket.
Start the Engine
Finally you need to start your Mustang and let it run for a few minutes to burn any leftover throttle body cleaner in the intake. Now your pony will idle better and this should solve stalling issues in many cases.