How Do I Fix An Unstable Idle On My 2001 4.2 L'001 Ford F150 4 2 Liter Engine

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The idle air command valve — also known as the "idle speed control valve" — regulates the idle speed of your engine. This is controlled by the engine'due south figurer. Sometimes parts go bad, which results in your machine idling strangely or stalling. Check to run into if your idle command valve is performance properly before attempting to replace it.

1
Look for a high engine idle. A common symptom of a faulty idle command valve can be a high idle. Starting time the engine and look at the tachometer on the dashboard. Most vehicle's engines volition idle at our below ane m RPMs. If you lot are familiar with your engine's normal idle, compare that to its current RPMs.^[i]
- If the vehicle'due south engine is idling well above 1,000 RPMs, it's probably also high.
- Vacuum leaks can as well crusade a high idle.
ii
Pay attending to depression idle or stalling. Aside from high idle issues, low idle and even sporadic stalling can both exist attributed to a bad idle control valve. Once more, start the engine and compare how information technology is running at a stop to how information technology normally runs. ^[2]
- If the idle is depression and inconsistent, it may be due to an issue with your idle command valve.
- Low idles could also be acquired past vacuum leaks.
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3
Look for signs of a vacuum leak. If your engine is idling poorly, endeavour to diagnose whatever possible vacuum leaks that may exist causing it. Visually inspect the vacuum lines in your engine bay for signs of damage such as cracks or overly worn areas.^[3]
- Remove a vacuum line and connect it to a vacuum estimate to mensurate the level and consistency of the vacuum.
- You tin can also try spraying a soap and water mixture on the lines to look for bubbling at the signal of a leak.
iv
Take notation if the check engine calorie-free comes on. The check engine light in your vehicle is designed to plow on if the Engine Control Unit (ECU) identifies an issues with how the engine is running. Look at your dashboard; if the check engine light is on in conjunction with idle issues, information technology may be because the idle control valve is malfunctioning.^[4] ^[5]
- The check engine calorie-free looks like a simple drawing of an engine.
- A cheque engine light in conjunction with idle issues tin be indicative of a faulty idle control valve.

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1
Use a code scanner to check error codes. If your vehicle was congenital prior to 1996, you will need an OBD I scanner. Vehicles made after 1996 volition need an OBD Two scanner.^[6] Connect the lawmaking scanner to the port beneath the dashboard and turn it on. Once connected, apply the scanner to bring up the error codes making the cheque engine lite come on.^[seven]
- In some code scanners, information technology will provide the English description of the fault code on the read out.
- If your code scanner does non, you will demand to look upwardly the code the scanner shows y'all to find out what it is.
ii
Start the engine and take note of the idle RPMs. Insert the central into the ignition and offset the engine. Wait a minute for the engine idle to level off, then apply a pen and paper to write down the RPMs that your engine settles and idles at.^[8]
- Y'all may need to let the engine run for a few minutes in guild for information technology to come downwardly to its normal idle speed.
- Keep the newspaper y'all write the RPMs on handy then you can compare it to the engine'south idle as you continue the test.
3
Close the machine off and disconnect the Idle Control Motor. With the idle RPMs noted, shut the vehicle back off and remove the key from the ignition. Open the hood and locate the Idle Control Motor. In one case you locate it, disconnect it.^[ix]
- The way to disconnect your Idle Control Motor will vary from application to application; refer to your vehicle's service manual for more specific instruction as to how to disconnect it.
- You tin commonly disconnect the idle control motor by unplugging the wiring prune going into information technology.
4
Restart the engine. With the Idle Control Motor disconnected, get back into the vehicle and start the engine over again. The engine should yet start and run without whatever issue despite the idle control motor beingness disconnected.^[ten]
- Exist sure to tuck the wiring y'all disconnected upward in the engine bay so it doesn't get caught in whatever moving parts.
5
Wait for a difference in idle speed. Let the engine to run for a infinitesimal so it settles to a consistent idle, then take note of any deviation in the idle RPMs versus the idle you observed earlier. If the idle has not inverse at all, it'southward probable because your idle control motor has non been functioning.^[11]
- If the idle control motor was working, disconnecting it should accept created a deviation in the engine's idle.
- This exam confirms there'south an upshot with the idle control motor, but not what the effect may be.
half-dozen
Shut off the engine and reconnect the Idle Control Motor. If you lot identified a deviation in engine idle RPMs with the Idle control motor continued and disconnected, ostend your hypothesis by reconnecting it and starting the engine once more.^[12]
- The idle should get dorsum to what it was when the idle control motor was concluding connected.
- Refer to the note you took about idle RPMs to compare it to your commencement reading.

1
Utilise a test light to check the wiring on a GM idle control motor. Have a test light and connect the negative pb to the torso of the vehicle. Press the test light into each of the 4 circuits on the GM idle control motor. Each circuit should make the exam low-cal flash or get from vivid to dim while the engine is running.^[13]
- If the test calorie-free doesn't flash on each circuit, the issue is coming from the ECU, not the idle command motor.
- If the examination lite flashes properly, information technology means the idle control motor needs to be replaced.
ii
Measure the resistance of the solenoid in a Ford. Locate the idle control motor in your Ford vehicle and place the two electrical pins on the solenoid. Connect an Ohm meter to the two and measure the resistance betwixt them.^[fourteen]
- Fords are designed to operate with the resistance in the solenoid in a range between 7.0 to 13.0 ohms.
- If the resistance is outside that range, the idle control motor needs to exist replaced.
three
Use a bidirectional scan tool to increase idle speed in a Chrysler. Connect a bidirectional scan tool to the same OBD port you would plug a lawmaking scanner into. Use the command in the browse tool to increase the engine'south idle. If the engine idle does non increment, information technology means there is an issue at the idle control motor of its excursion preventing the signal from changing the idle.^[fifteen]
- Y'all tin can purchase a bidirectional scan tool at your local motorcar parts store.
- Make sure the wiring harness is firmly connected to the idle control motor before conducting this examination.

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Question

How exercise I know if my vehicle has a trouble with the idle air command valve?

Hovig Manouchekian is an Machine Repair and Design Specialist and the Manager of Funk Brothers Auto, a family unit-owned business operated since 1925. With over 30 years of experience in the automotive industry, Hovig specializes in the process of auto repair and maintenance. He is also very knowledgeable in mutual automotive bug and needs including engine repair, battery replacement, and windshield accompaniment and maintenance. Hovig's cognition and hard work have contributed to Funk Brothers Auto winning Angie's List Super Service Award for 5 sequent years.

Automobile Repair & Design Specialist

Proficient Respond

If your check engine low-cal is on, that may help with the diagnosis. Also, if you have a modern vehicle with an OBD2 arrangement, you lot can cheque your idle air through browse tools. On older vehicles, try to cheque the resistance that'south going to the valve from the vehicle. You can besides endeavor to manually activate it to see how the automobile reacts—yous may be able to isolate the trouble to the valve.
Question

When I slow downwardly or when I finish at a red light my car dies. Could this be due to the idle air control valve?

It's possible. A faulty idle command valve can leave the engine idling at too low an RPM for it to go along running.
Question

The engine only runs when my foot is on the gas pedal. What's the deal?

Information technology'southward possible that a faulty idle control valve can get out the engine idling at likewise depression an RPM for it to continue running.

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Commodity Summary Ten

To bank check if an idle control valve is working properly, start by turning on your engine and letting it run for a minute or 2. Then, when it'due south at an idling speed, accept note of the RPMs in your automobile. Adjacent, turn the engine off and disconnect the idle control motor nether your hood. Once it's disconnected, constrict the wire out of the way, restart your car, and wait a minute or two earlier checking your RPMs. If your RPMs are the aforementioned both times, your idle command valve isn't working. For tips on how to bank check an idle air control valve in a GM or Ford car, read on!

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