2000 Ford Explorerer rough idle When cold

There are several possibilities for this problem. A "cold start" sequence is suppose to activate based on water temperature and the signal from the water temperature sensor. This makes the fuel rich and adjusts timing to make the engine run better when cold. It works like a choke only it is electronic.

There may be 2 sensors with one making the dash gauges work and the other doing the engine controls. If not 2, then 1 sensor would do the whole job.

Another possibility is an air leak in the fuel system which makes the system bleed dry overnight. It is far less common on gas engines but happens a lot on diesels.

Some earlier Ford engines from 1984 to I don't know when they stopped on trucks, would use a step-up solenoid on the accelerator bracket that worked off water temperature. Sometimes a bad water thermostat would make the temperature controls malfunction the other way (High idle, clicking, low idle) that would stall and engine as the temperature vary.

If it's surging, make sure your radiator is full. Do a tune up, plugs, wires, etc. Put some fuel injector cleaner in your fuel tank. On a cold start the vehicle compensates for being cold by adding fuel. Once it warms up the computer tells it to quit adding extra fuel. If it is a bad sensor of sorts, check engine light should come on.

couple of things,if you a autozone ,pepboys or another automotive store around they can diagnose it for free,or you may want to check your idle air control valve aslo known as iacv its on your intake manifold close to your carb it could be clogged up with carbon from burned fuel build up.good luck

change the fuel filter and check the fuel pressure

Its cold start issues:----
Go through the list of help links mentioned below:----

Click the link :----

Cold start problem and vehicle shudder around 2500 to 3500 rpms
http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html
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Low idle when cold out side?
http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html
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Ford explorer 4.0 will not idle when cold?
http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html
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Automatic transmission shift lever hard to move on cold mornings?
http://technoanswers.blogspot.com/2012/01/automatic-transmission-shift-lever-hard.html
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Car won't start when cold?
http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html
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It can be issue with IAC( idle air control valve) causing the problem.

There are many other possibilities causing these idle issues. Engine idles rough.

There are few help links with solutions to troubleshoot such idle issues.

I suggest you refer the link below and follow its troubleshooting details:------

Click the link below:-----

Ford Expedition IAC valve replacing

http://technoanswers.blogspot.com/2012/12/ford-expedition-iac-valve-replacing.html

Bad miss at idle?

http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html

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Stumbling and stalling at idle after engine rebuild?

http://schematicsdiagram.blogspot.in/2012/03/stumbling-and-stalling-at-idle-after.html

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1999 Ford F-150 Idles rough and quits when gas pedal is pressed less?

http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html

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Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

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Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

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Cold start problem and vehicle shudder around 2500 to 3500 rpms

http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

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Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

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GMC Sonoma Stalls and idles low

http://technoanswers.blogspot.com/2012/10/gmc-sonoma-stalls-and-idles-low.html

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GMC Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

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1996 Camry intermittent engine failure while idle?

http://repairhelpcenter.blogspot.com/2011/10/1996-camry-intermittent-engine-failure.html

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Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

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Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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High Idle Problem

http://repairhelpcenter.blogspot.com/2012/10/high-idle-problem.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed?

http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html

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High rpm in neutral? Inconsistant high RPM in neutral?

http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

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Vehicle stumbling at idle and shows code 54?

http://schematicsdiagram.blogspot.in/2012/03/vehicle-stumbling-at-idle-and-shows.html

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Rough idle, staling and Erratic shifting?

http://technoanswers.blogspot.in/2012/03/rough-idlestaling-and-erratic-shifting.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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These details will help.

Thanks.

Here are the most common causes of idle surge, rough idle esp when cold, other symptoms include stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

it will have codes but the scanner in use doesn't have the right protocol for reading them
Indicates a faulty ambient air temp or BARO sensor so there will be codes

throttle position sensor

sounds like the idle control vale is sticking when it is cold. It is located on the throttlebody right at the air inlet

I am guessing here w/o much info, 1 of maybe 4 things, idle speed contoller motor, low fuel pressure, dirty air filter, or lastly, carbon buildup on the throttle body throat. When cold idle the carbon blocks off the little needed air and the engines will run rough or just die.