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Hello everyone-first i'd like to say this is a very informative forum that i have been checking out for a couple months.My car has a couple of problems one of wich is now that it is colder out when i start it in the morning it immediatly idles at around 2000 rpm for about 15-20 seconds and then drops down to 1100 rpm or so and from there it gradually settles at 700-750.To me it seems as though the 2000 rpm cycle is not needed because the 1100 rpm is sufficiant enough to warm the engine at start.What sensor or control tell the IAC to idle that high when it is cold.I got this car this past summer and it does not idle that high at start when the weather is warm out.Thanks for all replies!
Robert
 

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well, not sure but when cold out the engine idles high to warm up. i have not noticed if mine goes as high as 2000 but it does go up. it is normal for this to happen. i will check how high mine goes tomorow morning and let u know.
 

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...What sensor or control tell the IAC to idle that high when it is cold...
[/b]
The PCM uses the IAC valve assembly to control:

No touch start
Cold engine fast idle for rapid warm-up
Idle (corrects for engine load)
Stumble or stalling on deceleration (provides a dashpot function)
Over-temperature idle boost.
Air Assist to Injectors.

The PCM controls this and it's listed as a feature. Same thing happens to mine. Only solution I know, move some where warm. B)
 

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It is normal for it to idle high for the first 15-20 seconds when it's cold. Although, mine doesn't hit 2000, it usually goes a little over 1500.
 

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i checked it this morning and it went up to mmm 1800 maybe but only for a second then down to around just under 1500. it does not get below 0*c here very often so maybe if it did it would reach 2000 rpm idk. like i said only high for a brief second then starts to level out. hope it helps.
 

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A vacuum leak could cause it to idle higher than normal, but as others have said, a high idle on initial start in cold weather is normal. The PCM does this on purpose to heat up the O2 sensors quickly so the car can get into closed loop sooner and keep emissions down.
 

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We're only getting 'cool' temps now, but on a cold start up RPMs are up around 2200 for the first few seconds before gradually dropping down.

At the top of the firewall, under the hood, drivers side above the brake cylinder, there is a hose that I have heard air from at a sensor. At least it looks like a sensor, anyone guesses on what it is?


Also, would a weak fuel pump cause high RPMs on start up?
 

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Well, if you have a vacuum leak fix it. Otherwise the high idle is normal. This is the time of year when a lot of people complain about high cold idle (and TPMS lights and poor fuel mileage). The car hasn't changed, they just forgot how it behaved in cold weather.
 

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I think your idle is normal. My car when it's been cold recently (not that cold like 45 degrees) has bumped up to 2000 for a second then drops down to about 1100 where it stays for several minutes and drops down to about 800-850 until I start driving usually or the engine is warm.

The PCM controls it through the IAC and this really shouldn't be a big deal. It won't hurt the car, and will just help it warm up faster. A good way to expedite the process is rev the engine up to like 2500rpm manually it should drop down to 1100 right away.
 

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I just realized this post is 4 years old. Why did someone re open it? I was wondering how it had 1,200 views!! Feel dumb for posting now haha!
 

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Joe WI, it sounds like you're describing the black plastic vacuum manifold distribution box above the master cylinder. If any of the 4-5 hoses or the box itself is leaking, you need to repair/replace.
 

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This is normal as my 2005 Taurus and other vehicles do the same when the engine is cold. It may idle at a high speed longer depending on how cold it gets in your area, but I would be concerned if it doesn't idle down after a minute. I usually wait until the tachometer drops down to 1000 RPM before shifting it into gear.
 
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