Why does My Car Idle High and How to Solve the Problem?

An engine’s idle is like the heartbeat of the human body. Just one abnormal or unusual sound, and you know that there is some problem with it. Cars tend to idle high, low, or rough. But in this article, I’m only going to talk at length about the most frequently asked question. Why does my car idle high?

A problem under your vehicle’s hood is not good news. During such times, the chances of the car’s idle speed along with quality being subjected to damage are highly likely. This means that issues related to idle speed are warning signs.

So let’s find out the causes and everything else you need to know about idle speed problems.


What You Should be Aware of Before Reading on

Car idling high when driving or starting has several causes. But before we get into them, there’s something else you ought to know. At present, our advanced computer and fuel systems seem complicated, don’t they? But the truth is that the components involved in operating them are pretty much the same as they were a few years ago.

So it doesn’t matter if you have a classic or a new vehicle from your dealership lot. Many car owners have to deal with engine idle. More often than not, the idle doesn’t seem like its true self. This is a common occurrence that you might face while driving or when starting a car.

Several factors are involved when it comes to determining the speed of an engine idle. And below I have discussed all of these components. They are responsible for controlling or causing the speed of the engine idle to shoot up or dive down. I have even listed the different ways that you can adopt so as to resolve such kind of issues in the most efficient manner.

Why does My Car Idle High?


Via reference.com

What is engine idle? It is the running of an engine even when the car is not moving. Typically, the speed of engine idle is sufficient to keep the engine running properly without stalling it. The average idle speed in SUVs, trucks, and cars present in the US ranges somewhere between 900 and 1,100 RPM (revolutions per minute).

But sometimes the engine’s RPM tends to be lower or higher than the average limit for various reasons. Performance cars have racing engines, don’t they? So in such cases, the idle speed is greater than the limit.

In most scenarios, two major issues cause the speed of the engine idle to be higher than the required capacity. And they are:

  • Problems with the car’s idle control valve. Even the screw on the carburetor can develop such issues.
  • Air/fuel flow obstruction or vacuum leaks into the vehicle’s combustion chamber.

So the best thing that you can do at such times is hire professional help. An expert mechanic will carry out a thorough inspection. As a result of which you’ll know the exact answer to the question, why does my car idle high?

What are the Causes of the Car Idling too High?


Via thoughtco.com

Modern fuel engines come with an ECU (engine control unit). This particular component is responsible for controlling the motor idle. Even the electric throttle control feature is used for the same purpose.

So what does this tell you? That any malfunction in these two systems or the components that house the systems might cause the idle to rise or lower.

The valve that controls the idle air does an excellent job at handling the engine idle by performing the following function. It allows only a certain quantity of air to combine with the liquid fuel. And this creates a vapor that burns in the car’s combustion chamber.

So when such activity fails to occur, it tends to mess with the engine’s idle speed. But there are a few more engine components that can give rise to high idle when starting a car. Let’s find out!

Vacuum Lines


Via civicforums.com

Vacuum lines are created to control your vehicle’s internal vacuum tension present in the motor. So if you’re wondering “why does my car idle high?” then there might be a problem with the line’s intake gasket. At such times, this particular element tends to break or detach itself from the correct position.

Intake Gaskets


The gasket is installed to keep a check on the engine’s pressure. When a vehicle’s gasket falls, it causes the internal vacuum tension to escape. And this, in turn, results in elevating idle issues.

PCV Valve


Via w8ji.com

A car’s PCV valve is nothing but its crankcase ventilation mechanism. What it does is help in getting rid of vapors from your engine. So when it fails to perform its job, the engine idle starts to work at various abnormal speeds.

Air Intake

Air Intake

Moving the air into the vehicle’s engine is the only function of the air intake. A damaged or faulty air intake component causes more air to pass through. And this can be the reason of your car idling high in park mode.

Even a broken throttle bore gives rise to the same issue as it doesn’t have the ability to regulate the amount of airflow entering the engine.

Engine timing also plays a huge role in determining idle speed. When the timing isn’t right, the engine can idle either too slow or too fast.

So these are all the components responsible for controlling idle speed. And this means that they need to work correctly. So if your engine is idling slower or faster than it should, you ought to get your technician involved.

This reminds me of the time I had some issues to deal with my 4 channel amp that I installed in my car a few years back. I tried to do the inspection myself, but that didn’t get me anywhere. So I had to hire professional help to solve the problem quickly and most efficiently. Don’t hesitate to do that if your car is idling high. The sooner you address the problem, the better it will be for your vehicle’s engine in the long run.

Final Thoughts

So now do you know the answer to why does my car idle high?

Dealing with idling problems is quite frustrating, isn’t it? But all you need to do is identify the cause of the issue. Once you do that, figuring out the correct solution won’t take too long.

So please make it a point to check the engine idle regularly. But do so with the defroster and AC turned off. Otherwise, they might interfere with the idle speed.

Have you ever had to deal with an issue like this? Does your engine idle high or low?

Tell us all about your experiences and how you tried to solve such issues related to idling. The more reliable information we have, the better solutions we can come up with.

I hope you found the article interesting and informative. And most importantly, did it help in solving your problem? Do leave your comments and feedback in the section below.

Thank you for visiting. Have a great day!

About the author:Christian Olsen is the founder of SBestReviews. He writes articles about all kinds of devices that we use on a daily basis. His goal is to cover all types of topics with transparency, honesty, and cheerful enthusiasm. Articles created by him have not only product reviews but also useful tips about the daily struggles of using technology. And he has a knack for relating everything to his personal experiences to create content that readers can enjoy.

2 thoughts on “Why does My Car Idle High and How to Solve the Problem?

  1. rose nahona says:

    hi there i had a bad 02 sensor cars was shit using to much petrol i have replaced the up stream and down stream 02 sensors does it take a a little bit of time for the fuel to adjust my rev idles were crap how can i fix this

  2. John Parker says:

    It could be something simple an it can be solved with a quick fix or could be a symptom of a much bigger problem. Nevertheless, this article was very helpful. Thank you.

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