2001 Mazda B2500 Rough Idle

On the intake manifold,

Cleaning your IAC to fix rough idle on 2000 or 2001 Mazda MPV

1999 Ford ranger IAC valve repair

Mazda B2300 Idle Air Control Valves

How to clean the IAC valve Ford Ranger Forum

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 really rough, check for dirty or stuck EGR. It just slightly rough and also you have to depress gas pedal a bit to start, check IAC (idle air motor). If gas mileage is also bad check coolant temp sensor.

Dirty air filter, dirty throttle body...try 2 bottles of gas line fuel injector cleaner...has your car been parked for awhile? Heet gas additive will work on any low gas tank sludge that you may have. Hope this helps.

tune up,fuel filter,air filter,clean throttle body.

It can be issue with low fuel pressure,the fuel pump is getting old both needs to be checked.Also get the IAC valve checked.
Go through the related help links with similar problem,it may help:---
Click the links below:---
Engine Idles Rough and Dies? http://whatisbyme.blogspot.in/2012/05/1994-lexus-es300-engine-idles-rough-and.html

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van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

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runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

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Car still runs Rough after tune up?

http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html

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2006 kia rio runs rough http://technoanswers.blogspot.com/2012/10/2006-kia-rio-runs-rough.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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Rough idle, staling and Erratic shifting? http://technoanswers.blogspot.in/2012/03/rough-idlestaling-and-erratic-shifting.html

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These details will help.
Thanks.

ck fuel pressure ,map maf sensor.timing .

it sounds like a lambda sensor issue, the lambda sensor is located on the exhaust manifold, it controls the emisions, it also controls the air/fuel mixture to control the emisions, if it is faulty it could cause the engine to surge like you describe

gas or diesel ???

Dear Smoker.......Sounds to a trained ear that this little guy is gonna need a fuel pressure regulator. It is basically dumping an excessive amount of fuel with the black smoke and all and once it gets warmed up it runs a little better cause it's out of the closed loop cycle. Check the fuel pressure regulator...pull the vacuum line off of it and if you can smell gas or see gas drippin out....that regulator is junk!!! The pressure regulator is on the fuel rail on top of the motor by the way...this should cure your woes.....if not..please get back to me... I HOPE I COULD HELP!!!