The Jeep’s Idling High Problem | Explained and Fixed


The Jeep’s Idling High Problem | Explained and Fixed

When you turn on your Jeep, you may notice that it is a bit louder than you’re used to hearing.

This could be a variety of issues causing the problem, but it often suggests a high idle speed. Some Jeep owners run into issues with high idling, which is the rate at which the engine is running when the car is one but not moving.

Why Is My Jeep Idling High?

Why is your Jeep idling high? There are multiple reasons that an engine could be running at a high idle speed but in Jeeps this can often be linked to vacuum leak issues, idle air control (IAC) issues, or throttle malfunctions. If your check gauges light comes on, you should also make sure these items are addressed and that any light mechanisms are in good condition.

If you are aware of the common issues that cause idling in Jeeps, it can be an easy thing to recognize and then fix so that you can go back to enjoying your ride.

This article will be your guide to explaining what high idling is, why it happens in Jeeps, and how you can prevent it or stop it once it happens.

Why Is My Jeep Idling High?

What is High Idling?

High idling occurs when the revolutions per minute (RPM) in your engine is operating at a high speed when the car is on but not moving. This occurs when the car is in neutral or park, and the engine is warmed up.

You don’t always have to worry about this when the engine is cold, but if it has warmed up and this sound and high RPM continues, it may suggest further problems.

A high idle does not always mean there is a problem, so you don’t necessarily have to worry right away.

If you notice this is a consistent problem, there are some steps you should take to identifying typical problems that are associated with high idling. We will go over these likely causes in the next section.

If you have consistent high idling in your Jeep, there are some negative consequences, making it important that you identify these issues when they arise:

  • Fuel Waste: Leaving a car on for an excessive amount of time, especially when idling high, will result in fuel loss. Turning the car off instead of leaving it on for extended periods of time is actually more fuel efficient.
  • Residue Build-up: Fuel is not being burnt at its ideal temperature for driving, so excessive idling causing build-up of fuel on the cylinders in the engine.
  • Spark Plug Issues: This buildup will negatively impact your sparkplugs and prevent them from operating as efficiently.

High idling puts much more stress on your engine than standard idling, making these issues even more severe if the car is left to idle at a high rate for too long.

700 RPMs is around normal for idling, and if it is a few hundred over this number, you should address the issue right away.

Why Is My Jeep Idling High?

Why Causes High Idling in Jeeps?

To prevent high idling from occurring, which places greater strain on your engine and its components, you will want to identify the problems that are causing the Jeep to idle. There are some fairly typical high idling problems that occur in these cars.

Some of the common issues you should be aware of and check in the Jeep if you experience high idling are:

  • Diagnostic Trouble Codes: These are messages that are connected to the computer in your car to give you information about the health of your engine and other components about the status of your car. These codes can point to potential problems, and many car service places or auto part stores should be able to translate these for you to come to a clearer cause. There could be a malfunction with these codes that are either showing a problem that does not exist or are missing one altogether.
  • IAC Valve: The idle air control valve is responsible for controlling the idle speed in your Jeep. If this part is old or weak, it can make the idle engine speed raise or lower more than it should be without a controlling mechanism. If it is dirty, it will also not operate at its ideal setting.
  • Vacuum Leaks: Vacuums in an engine are responsible for maintaining a proper air to fuel ratio, and when this vacuum leaks, the engine thinks that its oxygen level is not high enough. This triggers the engine to work harder and therefore raise the RPM, allowing for high idle. 
  • Throttle Malfunctions: Often related to dirty intake valves or a crack in these valves, a throttle system that is not working properly can lead to high or low idles in a Jeep.

If your Jeep starts to experience high idling, these are the first things you should look at in order to address the problem properly.

How Do You Fix A Jeep Idling High?

Now that we know the problems that cause high idling in Jeeps let’s address how we can go about fixing them!

Knowing the common issues mentioned above can make your troubleshooting much less painful and allow you to reach a solution much more quickly!

You should first check to see if any service lights or check gauge lights are on in your Jeep. This is the car telling you that there is an immediate issue that needs to be addressed.

If the idling occurs after you check and fix these gauges, you will need to move onto the next potential cause. Getting your diagnostic trouble codes read can reveal other underlying issues.

You will next want to check the IAC valve. You will want to make sure you get this area serviced regularly so that it doesn’t lead to problems.

If you do notice high idling, you can check it by removing the valve or idle control motor and seeing a difference in RPM when the car is on. If there is no difference, then the motor is not working properly and should be replaced.

To check for a vacuum leak, you can use automotive smoke to see if any leaks out, soapy water to find bubbling in leaking areas, or check the diagnostics in more modern Jeeps.

Once you have identified the leak, you can either use an automotive tape or replace the hoses quite simply. Once one starts to fail, you may notice that others will soon as they are all about the same age.

The final issue you should check for if none of these fixes work is any issues with throttle malfunctions.

Because residue can build up and make your intake valves dirty, you should clean these areas with intake system cleaners or similar carburetor cleaners.

Making sure your throttle areas are clean can put your idle speed back to its ideal range.

Why Is My Jeep Idling High?

How To Fix A Jeep Idling High [Video]

Keeping Jeep Idle Speed Normal

Being aware of the issues that are common in the Jeep related to high idle speed will make it much easier to diagnose if these problems begin to occur.

Consistently checking these areas for prevention is the best way to avoid high idling in your Jeep.

While some of these issues are common to Jeep owners, they don’t have to plague your driving experience.

Keeping your idle speed consistent and in the normal 700 RPM range will allow you to get a longer life out of your Jeep.

High idling has long term consequences on the health of your engine, and by preventing or recognizing these issues early, you can keep your Jeep running smoothly!

Kern Campbell

I've had a passion for four-wheel-drive vehicles since I was a kid riding in the back seat of my Grandfather's Jeep Grand Wagoneer. I have owned a lot of vehicles over the years. They each have their pros and cons and I look forward to sharing my knowledge with you so you can find the vehicle that's just right for your needs.

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