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What could cause a ford ranger 2003 to have a high idle speed while in neutral or driving. we have replaced the IAC, and the throttle position senor, and it's pigtail scene the trouble of high idle st

We get a code reading of 122

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Ever notice how a normal working vehicle will have high RPM upon initial start up? Then it will go from 1000 RPM down to 600 after a few minutes? This is because it has working temperature feedback to the ECU. After the vehicle has warmed up, it automatically adjust the fuel / air ratio and RPM level. If your car thinks its cold all of the time, it will maintain this higher RPM. Even if you see the temp gage working on the dash, there may very well be a second, separate temp sender for your ECU. One is usually located on the radiator, and the other very near to the thermostat housing.

Posted on Nov 28, 2014

Testimonial: "the idle on this truck is very high, sounds like someone trying to blow it up with their foot to the floor, then it will get eradicate before going back to supper high. we had replaced the mass air flow, o2, and the heat senor near the thermostat, because of low power and a miss. we had not solved the miss problem even though we put a tune up in it and changed the coil pack. however, it ran better for a moth. when the missing started again we checked plugs and wires. when we statred the truck again the high idle started. We checked over everything to see if something was knocked loose, we found nothing. We have checked for vacuum leeks and could find none. that is when we put on the new IAC, and throttle position senor. these made no change"

  • Eric Cross
    Eric Cross Nov 28, 2014

    The air allowed into the intake side of the engine is regulated by the position of the butterfly valve. If there is a leak on the valve closest to the engine (commonly called throttle body) it will be as if the throttle is opened more than it actually is. Or, the throttle could have some obstruction preventing movement to the full shut position. The throttle body butterfly valve should return itself to full shut and should not easily be opened by the air alone rushing past it. Try removing the rubber intake boot so you can access the butterfly valve. Start the vehicle and observe the valve position. if it flies open, then it either has slipped on the shaft or the return to shut spring is missing or broken. if you press the valve shut with your index finger, does that change the idle?


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You may have a vacuum leak(hose/gasket leaking) causing the problem. the other thing is the idle speed may need to be set and there is a procedure that should be done at a shop to get it right. you could have an EGR valve that is hanging open just enough to cause a vacuum leak to cause this.

Posted on Nov 28, 2014


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SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

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Posted on Jan 02, 2017

  • 44 Answers

SOURCE: high idle 1997 Madza 626 4 cylinder auto transamission

The PCM controls idle speed to ensure good driveability. The PCM will only attempt to maintain the desired idle speed when it “knows” the throttle is closed. A throttle switch or the TPS input is used to determine when the throttle is in the idle position. Motors and solenoids are used by most PCM’s to control idle speed. Many PCM’s are programmed to attempt to control the idle speed by adjusting spark timing and then by controlling the idle speed actuator. Some computers of the early 80's did not control idle speed.

Posted on Oct 19, 2008

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SOURCE: Check engine light is on and high idle (1500rpm)

Some times the E.G.R. will stick half open. This will make the engine surge or have high idle. Try replaceing the E.G.R. located under the upper intake. Do not go with after market E.G.R. The spring in them are to powrefil and the E.G.R. wil not open. Also try replaceing the O2 sensors. This could give the engine more fuel thus a higher idle. Some vehicles the T.P.S. can be ajusted, do some checking to see if yours is adjustable.

Please contact me if your problem presists.
Thanks, Charlie

Posted on Feb 03, 2009

  • 77 Answers

SOURCE: Saturn SL 2002 High Idle

Intake manifold gasket. Leaking where intake meets head.

Posted on May 07, 2009

  • 3 Answers

SOURCE: 2004 Honda Civic -Code P0122 Throttle Position Sensor Voltage Low

yes, this is the case of a failed throttle body, in which case it needs replaced, the car is getting too much fuel causing the high idle. this needs replaced asap. you could proably find a small independant honda shop that could do the work for less.

Posted on May 12, 2009

  • 1 Answer

SOURCE: High idle speed- Nissan N16 Pulsar/ Almera

Battery not charging well when airconditioner on ( also engine speed not increase when air conditioner on )

Posted on Jul 30, 2009

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2003 ford explorer idle surged on me driving. Stopped and put in neutral went up to 3000 rpms. Fast idle now

Given all the electronic sensors that could cause this problem , your best bet is to take it to a qualified repair shop where they have advanced testing equipment . Just so you do spend all your money replacing parts ,,here is just a couple that can cause this problem ! Idle air control valve , throttle position sensor , vacuum leaks , map sensor . dirty throttle plate . mass air flow sensor . A qualified repair shop has a scan tool that can check data for all these sensors .

Jun 29, 2016 | 2003 Ford Explorer

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Why does my 1992 Ford Explorer idle too fast?

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Nov 02, 2015 | Ford Cars & Trucks

1 Answer

Can the crankshaft position senor cause high idle on a ford ranger

no --The purpose of the crank position sensor is to notify the ECM when the piston is in the correct position to create a spark for the cylinder.
regardless of the rpms of the engine, it sends a signal to the ECM and in the program of the CPU in the ECM and the ECM decodes to advance or adjust the spark after TDC ( the spark in relation to the ignition timing.)
High idle is cause by the idle speed sensor, MAP,MAV and VAF sensors . have the fault codes read a nd look for such a sensor fault.

Nov 28, 2014 | Ford Cars & Trucks

1 Answer

Gas pedal gets stuck and keeps the car going cant stop without turning the car off

dont drive it. find the cause and fix it now.
Hot and cold engine or BOTH>?
1995 Tracker, no tranny , no 4wd , on engine options stated.
Exact high RPM in neutral, not stated...... 1500 is normal cold.
keeps going in Neutral. (nah , you have 5 ways to stop any car.
key, hand brake, foot brake and neutral. and with 4wd, 1 more neutral.
keep that in mind driving any car.
this car has up to 3 throttle cables that can stick. and more!

1: floor mats hit the pedal>? ala. Toyota style (lawsuits)
2: the three cables are, throttle. , cruise and A/T transmission kick down cable. if car is M/T and no cruise it has 1 cable.
so disconnect it, throttle fixed? (disconn,. 1 by 1, bingo?

no cure?, then its not the pedal , you meant just high idle.
yes, replace the cable or bad parts three.
ok say its not the cables.. (tests proved that)
the 95 came with 2 engines, 8valves and 16valves,
they work differently (8v love so race, 16v loves to stall)

1: ISC Stuck open, common.
2: 8v, any air leaks at all , will cause super high idle speeds.
3: throttle valve in the throttle body is stuckopen (gunk) or the return spring broken (very very rare the latter,in fact never heard of one breaking)
4: IAC (thermal idle control stuck open ,(my 97 was). and lots more.
5: on the 16v it takes 2 failures. to make high idle.
gross rich running engine (cold engine its normal) and any air leak
once hot the engine can not race unless there is huge overfueling
and an air leak.
6: the 8v has this device on the side of the throttle body.
called a dash pot. its just a fast idle vacuum servo.
if stuck open the engine will scream full time....
7: ECU stuck in limphome, can cause too high idle speeds.

we need to know which engine
8v or 16v first.
then does the idle race hot or cold or both (engine temperatures)
if it races , then how fast?, RPM the dash tachometer tells you that.

it can be as simple as a 50cent hose cracked.
to a dead ISC. (idle speed control) IAC is thermal idle air controller.
the IAC must be closed on a hot engine,
if the the engine never gets hot,it will scream full time.

Feb 13, 2014 | 1995 Geo Tracker

1 Answer

Car engine idles really high then really low, why?

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

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Engine quits at idle?


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High Idle Problem


While stop engine idles like cylinder missing?


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


High rpm in neutral? Inconsistant high RPM in neutral?


Vehicle stumbling at idle and shows code 54?


Rough idle, staling and Erratic shifting?


While stop engine idles like cylinder missing?


These details will help.


Feb 15, 2013 | 2003 Pontiac Grand Am

1 Answer

92 buick century when i start it up the idol goes way high like its going to blow put in drive it jerks and eats alot of gas

more then likely it is the IAC thats bad. clean or replace the IAC. more causes are--- erratic idle (including high idle speeds) can be caused by a faulty throttle position sensor (TPS) - a common problem. and check for a bad vacuum hose also. good-day ! clean IAC first ! to see if this helps then go from there.

Jan 15, 2012 | 1992 Buick Century

3 Answers

My 2000 ranger idles really low and sonetimes even dies. ihave to push gas pedal little bit to get it started

The Idle Air Control (IAC) is not working.... This is a very common problem and very easy to fix. The IAC will run you about $50 (USD) and the only tools needed is a 8mm socket. Disconnect the electrical connector, remove the 2 8mm hex screws, remove IAC. Reverse order to install.

It looks like the picture below


Mar 25, 2011 | 2000 Ford Ranger SuperCab

1 Answer

I have a 1998 Acura 3.0 CL and the radio had an error 3 last week. I had to take the console and radio out in order to find the radio serial number and got the radio code from Acura, since mine was...

I don't see this as related to the console. This issue is usually caused by the idle air control valve. The valve may be bad or possibly the wiring. If it's the wiring, normally the computer will turn on the engine light.
You can check the valve operation using a common obd2 scanner in data mode.
Here is more info from
Engine idle speeds are controlled by the PCM through the Idle Air Control (IAC) valve mounted on the throttle body. The PCM sends voltage pulses to the IAC motor windings causing the IAC motor shaft and pintle to move in or out a given distance (number of steps) for each pulse (called counts). The movement of the pintle controls the airflow around the throttle plate, which in turn, controls engine idle speed. IAC valve pintle position counts can be observed using a scan tool. Zero counts correspond to a fully closed passage, while 140 counts or more corresponds to full flow.
Idle speed can be categorized in 2 ways: actual (controlled) idle speed and minimum idle speed. Controlled idle speed is obtained by the PCM positioning the IAC valve pintle. Resulting idle speed is determined by total air flow (IAC/passage + PCV + throttle valve + calibrated vacuum leaks). Controlled idle speed is specified at normal operating conditions, which consists of engine coolant at normal operating temperature, air conditioning compressor OFF, manual transaxle in neutral or automatic transaxle in D .
Minimum idle air speed is set at the factory with a stop screw. This setting allows a certain amount of air to bypass the throttle valves regardless of IAC valve pintle positioning. A combination of this air flow and IAC pintle positioning allows the PCM to control engine idle speed. During normal engine idle operation, the IAC valve pintle is positioned a calibrated number of steps (counts) from the seat. No adjustment is required during routine maintenance. Tampering with the minimum idle speed adjustment may result in premature failure of the IAC valve or improperly controlled engine idle operation.

TESTING The IAC can be monitored with an appropriate and Data-stream capable scan tool

Oct 02, 2017 | 1998 Acura CL

1 Answer

How do you lower the idle

The idle speed on this vehicle is controlled by the engine computer. If it seems to be idling high, the idle air control valve (IAC) may be stuck or faulty. This can sometimes be corrected by removing the IAC and cleaning carbon deposits out of it with carburetor cleaner. Some sensors can also cause a high idle, such as air temperature sensors or throttle position sensors. If everything else seems to be OK, however, the IAC is the best bet.

Dec 17, 2009 | 1994 Ford Explorer Limited

2 Answers

When staring my 99 Ranger the engine runs at an increased RPM for a few seconds before idling down to the correct RPMs. It seems to be last for a longer period of time the warmer the engine is

Hello... The first thing to determine is whether the high idle is caused by a mechanical issue, such as a faulty idle air control sensor (IAC), or a throttle plate that is not closing, or if the idle speed is actually being commanded high by the computer. One of the easiest ways to do that is to simply unplug the IAC with the truck at idle, and allow the engine to slow to the "minimum air rate" or base idle speed. There is no published spec, but if your minimum idle speed is in the 500-600rpm range in park, thats close enough. There is no normal service adjustments required, but if something is keeping the throttle plate from closing, then you'll have to correct that.
Now...when you unplug the IAC, you will find either a normal minimum idle, or no change at all. If there is no change, and the throttle is not sticking open, suspect air is getting around the throttle plate, which could be a bad IAC, because thats exactly what it does, it allows air to enter the engine around the throttle plate. Normally the computer has complete control of the IAC, but it can fail mechanically, so it must be checked.
The next scenerio would be the idle speed being correct when the IAC is unplugged, and then going back up when it's plugged back in. This would indicate the computer is actually commanding the idle speed high....and this is where the correct scan tool becomes so important, because it allows the techincian to see this information right from the computer. From this info the problem can be determined and repaired.
Good luck..i hope this helps...please take time to rate me a fixya.

Jul 23, 2009 | 2000 Ford Ranger SuperCab

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