IAC changed, still won't idle cold

Jan 15, 2006 4 Replies

After changing the IAC on a '94 Aerostar (3.0), is there something else required before it works ??



Still have the same problem: cold start it revs up normanlly but after 10--15 seconds it dies. It DOES idle after driving a block, but it's rough.



What other causes should I be looking at ??



thanks



All the normal maintanace things. Did you change plugs, wires, and ignition cap? Check all small vacuum hoses carfully for cracks and leaks? PVC valve? Clean or check MAF sensor if you have one?

Start you truck at night and look closely at the ignition wires coil and cap. See any light show?

Bob

oops, sorry, I should have said --- it had a complete tune up about

6 months ago and it ran better than ever.........until the idle problem

started a month ago. So some of the things you mentioned I have to assume were covered. But yeah, could have developed a vacuum leak since then.

I remember someone saying they had to "reset the codes" or something similar. How are they reset ?? ( eg, after changing the battery I think it resets itself by just driving it or letting it idle a long time )

Clean the throttle body.

Fred

Check all the vacuum lines: PCV, EGR, CANP, Climate control. You'll find them all neatly illustrated on the emissions calibration sticker under the hood. What you are experiencing is 10-15 seconds of fast idle, where the car's computer sends the signal to the IAC to allow the engine to rev at higher rpms to warm it up. Then the signal stops to allow the engine to idle normally, except in your case where you have something gone awry it doesn't. I'm pretty sure that's it in laymen's terms.

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