[Poppy]

The Idle air control valve is commonly called the IAC, or Idle air bipass valve IAB when it fails electrically, or gets gummed up and sticky, it won't properly control air into the engine and the engine's idle will suffer.

The engine may be hard to start. A faulty IAC may not throw a diagnostic troubleshooting code.

What does the IAC do? How does it work?
Ford Fuel Injection
Check and clean your IAC
Ford Explorer IAC Fix .: Articles
TheOldWizard Has some issues with the video I'll link to below, and while I agree with him, I think that overall the video is helpful and worth looking at.

First, the example Idle Air Control/Bypass (IAC/IAB) motor they showed during most of the video is very different from the style used on most (all?) Ford vehicles. They showed a Ford design briefly and described it as one with an internal pintle.
Second, they said specifically not to spray cleaner on IAC with internal pintles. BS ! Any carb cleaner will work. Most will dry quickly. Just make certain to not leave any gunk.
Third, I have seen IACs work properly when warm, but stick when cold so their suggested testing procedures may not be perfect. In other words, you could pass all of the tests and still have a sticking IAC when cold.

youtube video
[ame=http://www.youtube.com/watch?v=406BTo4JE3A&feature=player_embedded]YouTube - Emission System - Idle Air Control Motor Testing & Replacing - 1 of 2[/ame]

 

[Headdi]

Thx , poppy this thread helped alot with my wife's car an escort.

..I actually hate the d&#$ thing but it gets good gas mileage and its all we have that we can rely on right now...lol... I can't give it to much grief . And tho it has no tilt, Cruz, or power anything, just 5 speed, it does have the most important Coastal Carolina attribute, and that my friend is air conditioning!...lol...yeah hard to live without that down Here, so all in all pretty thankful. But I have to get old truck up and going again..can't pull anything with that escort , although have used it like a truck, small boats in top and filled to the gills..lol..=)