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2003 Ford Windstar abnormally fast idling when cold

Tiny
DICLEMEG
  • MEMBER
  • 2003 FORD WINDSTAR
2003 Ford Windstar 42000 miles

Hi,
When startup, the idle is way too high, and for the first ten minutes or so, I can drive 20mph without touching the pedal. When it gets to full operating temperature, then the idle is stable and where it should be. If the engine is anything other than full warm operating temperature, I'll be idling at 1100 at least.

I cleaned the IAC valve, and throttle body and cables. I noticed the IAC valve was fully seated when I was cleaning it and disconnected it, I'm not sure if its supposed to fully seat closed or not. I put my finger in to spring it shut and it closes but springs back open, I think was 1/4" open when not connected. IS THE IAC VALVE SUPPOSED TO BE CLOSED when no power going to it?

I inspected all the vaccum lines, everything looks fine and connected. The engine does seem to make a high whine.

I had the autozone guys check the code and the P1504 came up, but I think that was because I tried to start the engine a few times with the IAC valve disconnected, and by the way, the engine would fire and then shut off.

Yesterday, when warm, I disconnected the Throttle sensor to see what would happen and engine revved high.

Please assist. Thank you.
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Friday, April 11th, 2008 AT 10:20 AM

9 Replies

Tiny
BLACKOP555
  • MECHANIC
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Will the idle come down if you step on the gas a few times, reving up the engine about halfway, once its been warmed for a little bit?

Clean the throttle body, check the pcv valve and check for vaccum leaks.

Sounds like everything is good to me. It is supposed to idle high when cold out to get the engine up to proper temperature.
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Saturday, April 12th, 2008 AT 9:48 AM
Tiny
DICLEMEG
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Thanks for responding.
Let me be clear. When its cold, if I give it gas, it appears to take its time coming back down. If fully warm, it comes down faster, but maybe a slight laziness.

When I start when cold, it'll idle high, like 1600rpm, and for first ten minutes or so of driving, it'll go itself, itll get to 20mph and even shift into second, without me giving it any gas whatsoever. Unless the engine is very warm, say, after 30 minutes of driving, itll seem to want to idle around 1100rpm, or maybe sometimes 900. Only unless I'm driving for long period of time does it get to 750rpm.

And, especially when cold, when I am travelling with velocity, and have to brake ahead, it'll seem like theres a poor mans cruise control on, it seems to coast forever, and I'm constantly holding the brake and way too early, for any braking ahead. It is much more dramatic when cold.

I changed the PCV grommet, changed the throttle sensor, cleaned the IAC valve and throttle, and cables.

I have no engine codes at all. I did have one when I changed the TPS sensor.

I shook the PCV valve, it makes noise.

I checked all vacuum lines in front of engine and did the best I could checking the lines in the back of the intake without removing the cowl.

Someone said something about checking the EGR valve, and I did not yet, for I don't know how.

Now what do you think?
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Monday, April 14th, 2008 AT 8:45 AM
Tiny
BLACKOP555
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Can you get a iac module from the junk yard and give it a try, it might be the iac since its taking its sweet time to come back down, sounds like it might have some build up internally, that you cannot clean out, by the way.

The EGR shouldnt cause an idle problem like that.

You may have a bad coolant temp sensor, not the switch. You dont want the switch, that is the one that sends the temp to the guages, the sensor if you measure its ohms it should be close to the IAT sensor, make sure it sat overnight before checking.
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Monday, April 14th, 2008 AT 2:12 PM
Tiny
DICLEMEG
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You know something, it feels like when I drive, im using the brake more than the accelerator. And I have one of those electronically adjustable pedals, maybe somewhere between the pedal and the throttle is sticking, but I don't think so.

Another thing is that the prior owner has one of those remote starts installed, I wonder if that is what is messing things up.

Im not getting any codes, however, I keep thinking I have that isolator bolt problem.
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Tuesday, April 15th, 2008 AT 9:10 AM
Tiny
BLACKOP555
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You have no idea how many problems remote starts can cause to a vehicle, I have heard of them causing idle problems, but the IAC module could be shot.

Probably time to take it in to a shop and see what they say about the IAC.
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Tuesday, April 15th, 2008 AT 5:41 PM
Tiny
DICLEMEG
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Well if the IAC valve/motor is bad, shouldn't it trip some sort of error code, maybe like "too lean" or something? Im getting no error codes.
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Thursday, April 17th, 2008 AT 8:53 AM
Tiny
BLACKOP555
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IF the IAC module is bad it may or may not throw a code, it will not throw a lean code, has nothing to do with fuel mixture, just idle.
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Thursday, April 17th, 2008 AT 3:44 PM
Tiny
DICLEMEG
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The IAC valve is completely clean, though not fully seated/closed when disconnected, but I think thats normal. But get this. When cold, I started engine, it revved high initially like 1900 and within ten seconds of starting, I disconnected the IAC valve, and the rpms dropped to 600, and then after a minute or so the engine finally died. Does this mean I have a vacuum leak, since the engine continued to run with the IAC valve disconnected, though only for a minute? And if yes, do I need to remove the cowling to check the rear vacuum lines or can they be checked when on a lift?
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Friday, April 18th, 2008 AT 8:16 AM
Tiny
BLACKOP555
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The engine still should run with the IAC unplugged as long as your not idling with ac on.

To check for vaccum leaks take a can of carb cleaner and spray all around the engine components and lines wiht it, if idle goes up, theres a vaccum leak.
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Friday, April 18th, 2008 AT 6:43 PM

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