Idle Air Control Valve - IAC?

It does sounds like the IAC is not working correctly here is a guide to help walk you through the steps to replace it with diagrams below to show you how on your car.

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

and

https://www.2carpros.com/articles/stall-at-idle

Check out the diagrams (Below). Please let us know what happens.

That fixed it! thanks for the guides they helps help this site is great.

Good to hear, please use 2CarPros anytime we are here to help.

My truck has recently been idling abnormally high when cold started. I unplugged the IAC and it drops the idle then plug back in and it usually stays lower. I cleaned the passages in the IAC, but the problem still occurs a few times a week. Does my IAC need to be replaced?? Is the computer doing this? Hope not.

John

Has the check engine light ever come on?

The check engine light has not gone on while this problem started, pretty sure it's the IAC valve.

John

Chances are you are right, but I hate to recommend things if I am not sure. Without the check engine light, it is a guess. That is the part I hate.

When replacing the IAC are there any reset procedures or manual calibrations that must be done on this vehicle?

No adjusting should be done make sure the air way clean before installing the new one after installing turn key on for about a min then off for a min start and let it idle

Do I need to do anything other than replace the IAC valve like re do something to the computer? in my 2000 ford ranger 2.5L

No, you don't have to do anything. If there's a code in the computer (check engine light), then you'll need to turn it off with a scan tool. But the computer has an internal memory and will recognize the new part without you doing anything.

If you disconnected the battery, the computer will reset itself. It may seem like it's driving messed up for a while, but that is only the computer in "re learn" mode. It'll clear up.

I have a 1999 Ford Ranger 2.5L I4 5 speed manual transmission. Occasionally, the engine will not return to idle speed between shifts. The idle will keep the engine @ rpms estimated above 2 - 3K. I have replace the Idle Air Control valve (IAC) but the problem still exists. It only seems to be a problem after the vehicle has been driven and sits for some time. If I start from a cold engine I don't notice the problem but after sitting for 30 minutes to an hour or so is when the problem seems to develop.

Could it be temperature related?

Thanks,

Dave

Has the check engine light come on?

[quote:ef23a36f3e="Jacobandnickolas"]Has the check engine light come on?[/quote:ef23a36f3e]

No, the check engine light has not come on!

Sorry, I should have noted that in my question.

Dave

My idle is too high and I would like to know how to adjust the idle on a 1999 ford ranger 6 cyl. thanks

The computer adjusts the idle on your truck automatically.If it is too high, you most likely have a vacuum leak.Pop the hood and see if you can hear a loud hissing noise, if so locate it and repair the hose as required.Fords have issues with the lines from the PCV valve to the intake leaking.Also try spraying the intake carefully with carb cleaner while it is idling, if the idle changes, you have sprayed a leak.If there are no vacuum leaks, the Idle Air Control Valve may be bad, but check forvacuum leaks real good first. If the check engine light is on, have the PCM scanned for any trouble codes, this may point us in the right direction for a fix

My truck has been idling very rough this year, recently my "98 ranger has been stalling at most every stop light or sign. It is a manual 5 speed ~ 2.5L engine. I have been working on this on and off for the last 6 months. I changed all of the spark plugs & spark plug wires. What advice can you give me to remedy this? Thank you for taking the time to help.

The iac needs removed. Have a helper turn the key from off to on. There is a pintel valve that should move on the iac. Also, check for vacuum leaks.

I have 1998 Ranger 2Wd, 2.5 liter engine. When I push the clutch in to coast to a stop the engine continues to race at high RPM. If I let out the clutch the engine is dragged down to appropriate speed, but if I push the clutch back in the RPMs race back up to high speed until I come almost to a complete stop. Then the RPMs drop to idle speed.

This sounds like the IAC needs to be replaced here is the location in the diagrams below. Check out the diagrams (Below). Please let us know what happens. HEre is the IAC location in all three engines that come in your truck.

The Check Engine light wasn't on until TODAY! It just came on, so I don't think that was the cause. I think that is just another symptom.
The problem seems to be worse when the A/C is running. I'm in Texas so that's just about all the time. When I push in the clutch to coast to a stop the engine races at about 3K RPM until I come almost a complete stop. Then it slows to idle speed.
Another thing...when the A/C is on and at idle, like at a stop light, the engine surges to about 1200 RPM for a few seconds then slows to about 600 RPM (pretty slow), almost slow enough to die, for the same amount of time. It alternates back and forth unto the light changes and I start up. It doesn't do that when the A/C isn't on.
Thanks for your help on this. I'm stumped.

This might sound like a strange question but... Have you checked all the fuses under the hood and inside the car? And does the problem ONLY occur when the A/C is on?

Lazy or dirty IAC valve remove and clean 1st or replace
Check AC if low on refrigerant

4 cyl engine runs good. Sometimes rough idle. When I press the accelerator to the floor and let go, the engine dies. Error code says IAC. I have replaced the IAC. No improvement. I replaced the TPS.
Seem to work for a little while. Error code, however, never went out. Problem returned and error codes are the same.

there is a lot more to a code than throwing parts at it.

the iac code means it cannot maintain an idle. it could be throttle body, base isle setting, wiring, pcm or vacuum leaks.

Roy

Hi this is Justin I have a problem with stalling when putting in gear on my 1994 Ford ranger with 4.0 and with a a4ld transmission I just wondering can a iac valve can cause my problem I unbolted the valve and turn the key to on to see if it is working I didn't see it was moving I just wondering if this is my problem with stalling when putting in gear

you wont see it move. it is a common failure. make sure you set the base isle to 500 rpm before hooking up the iac

Roy

To ASEMaster6371 so the valve inside the iac valve won't move when the key is on position no engine running plus I check the valve on ohms it reads 0.02 is this normal readings or not what's the normal readings on ohms for the iac valve..... my set on 20 ohms

ohms is ok but motor shaft sticks and cannot be serviced.

Roy

To ASEMaster6371 sorry for a late asponds so the readings off the iac valve is normal and also the part is bad if the shaft don't move I tried to clean it but it still don't move

once again, it is not servicable. you cannot clean the area that is bad. replace it,

Roy

Reset IAC and how to adjust AutoZone IAC it's adjustable an the factory Ford is not. I need to figure out how to reset the IAC on my truck the sequences and find out how to adjust AutoZone adjustable IAC for my 2.3. it is the $70.00 IAC.

Hello,

There is no reset for your vehicle's IAC Valve. It is controlled by the electrical connector which goes to the Power-train Control Module[PCM] or "computer". If the IAC Valve goes bad, it is simply replaced. Here is a link below for you to go to:

https://www.2carpros.com/articles/idle-air-control-valve-service
https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac


Thanks,
Alex
2CarPros

My car normally starts at 2,000 rpm than drops to 1,000 slowly. First time today it started at 1,000 rpm than bog down quickly to 500 rpm and continued, turned it off and over again same thing happen. Trying to run diagnostic but I'm lost and can't figure it out. Sometimes when it sits for a bit and is turned on it will start normally and will drive normally, other times it just sit there and bogs down.If the vehicle is turned off and on even minutes after it will start at a low rpm again than bog.I started my vehicle today it was a bit low on gas so I thought that was my issue, filled it up and I thought the issue was fixed. But like I said when I turn off, than on minutes later it will start at a bog.

Hi Aaron,

This could be an IAC but usually when these fail, the engine starts and shuts off quickly. However, if it feels bogged down then this could be due to a restricted air flow. The other thing it could be is the MAF itself. Sometimes these get dirty and they send incorrect readings to the PCM so it causes rough running or idle issues.

Here is a video on how to test the MAF. It is easy enough that I would start with that and go from there. Worst case you can test and replace your sensor if needed and then clean your IAC and see what happens. I included videos for both. Please understand they are not exact for your vehicle but the theory is the same.

Let me know if you have questions or what results you turn up and we can go from there. Thanks

https://youtu.be/p0ocaDmcAIM

https://youtu.be/rNQGEGvophg

Hello,

This could be a problem with your Idle Air Control Valve (IAC). I have included in the diagrams below the Ford Motor Company adjustment procedure for your vehicle's air control including what your idle speed should be set at . Please go through the guide and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros