A car that shakes when it is idle could be a reason to be concerned regardless of the brand and model you own. Although most vehicles shouldn’t exhibit it, there’s a variety of causes for it to happen, and each of them requires specific care.


  • Is It Normal for Car to Shake When Idle?
  • Reasons Your Car Idles Rough but Drives Smooth
  • How to Fix Car Vibration
  • Is it safe to drive in a Car with a Rough Idle?

Is It Normal For Car To Shake When Idle?

The simple response is a resounding yes. The issue is whether they’re manual or automated vehicles, they tend to shake at idle. This is due to the alignment and direction of the engine and its components with respect to the car’s body and chassis, as well as the tolerances between these components for bearings, for instance. The majority of the time, the shaking isn’t noticeable; however, it is important to be aware that the car is built to be this way.

If, however, your vehicle runs rough, is having trouble getting going, or shakes a lot during a stop that lasts longer than a few minutes, you need to look into the issue. Engine mounts that aren’t working properly could be causing your car to shake when you drive.

Reasons Your Car Idles Rough But Drives Smooth.

There are a variety of reasons cars shake in idle, but be smooth when driving. Here are eight possible causes for your car shaking in idle but being smooth during driving.

Loose gas cap

A gas cap can be among the main reasons for a sluggish idle since the cap isn’t secured enough, it may let air in the intake. If this happens, your engine must be more efficient to continue operating.

It is because it’s running in an air vacuum caused by the intake, without air from outside, that it must force into that vacuum. It could be caused by carbon lock if the gas cap is put on too tightly for a long time, and a portion of the fuel is vaporized to carbon particles instead of burning completely. This can make things harder, particularly starting the vehicle.

The best way to confirm whether your fuel tank is at fault is to inspect the cap on your fuel tank and then replace it if you think it’s clean. The price of a gas cap is not that much in comparison to the cost of an engine rebuild due to carbon lock; therefore, add it to your shopping cart today, and you’ll be grateful that you made the right choice.

Worn throttle position sensor

A damaged or worn throttle position sensor may cause problems with the idle of your car. It could not know the exact location of its rotation, so the engine is constantly trying to increase its speed but isn’t sure when to stop. This can result in an unpleasant ride when idle.

A throttle position could become stretched when the cable is set too tight, and this can result in the sensor for the throttle position not functioning as effectively as it ought to. Furthermore, it could cause similar effects, like a leaky gas cap and air leaking through a weak seal.

Bad or faulty idle air control valve

The valve for idle control is responsible for regulating the volume of air entering the engine during idle. If it malfunctions, the car will be running rough as it’s not receiving enough oxygen to burn the fuel that is in the combustion chambers.

The valve also has a small vacuum which is controlled through an engine vacuum. If it’s not functioning or something similar ruptures a hose, the engine will idle but with irregularity since there’s no vacuum.

A malfunctioning accelerator position sensor may cause your vehicle to shake when it isn’t able to determine how long the accelerator is pressed. It’s a sign that your vehicle is trying to accelerate faster than it is not supposed to, and the engine may be rough when it’s idle.

Another consequence could result in a delay when you hit the gas. This means instead of moving forward smoothly, the vehicle swerves either way or the other direction, as it takes time to get the car to react to your commands.

A malfunctioning idle air valve may result in a rough idle as well as other issues mentioned previously. If the valve isn’t functioning correctly, it can stop an engine from sustaining a consistent idle speed. This can be caused by leaks in the vacuum or issues with connections and hoses in the intake manifold.

Faulty fuel pressure regulator/ignition control module

If the regulator for fuel pressure isn’t working properly, it could cause problems with the idle of your vehicle. This is due to the fact that it controls the quantity of gas that is injected into the engine when it is idle. When there’s insufficient gas in these cylinders, the engines will not be able to ignite and then run rough.

One indicator that a regulator of the fuel pressure could be defective is if the vehicle has a rough idle, even when in gear, but not pressing upon the pedal.

A defective ignition control module can lead to problems that cause your car to shake when you idle, as it blocks your engine from getting started. It does this by sending an alert that informs the fuel injectors that it is time to ignite so that the cylinders can produce the necessary compression to begin.

If the engine isn’t working, you’ll observe other issues, such as your car crashing at red lights or stop signs because there’s not enough power to start the engine.

Oxygen sensor

A sensor for oxygen regulates the emissions gas levels inside your car to ensure there isn’t too much or not enough oxygen. It’s essential when idle as the computer of your car depends on this information to determine the ideal ratio of fuel and air.

If it isn’t sure what the proper levels are, then it could create all kinds of issues, such as a rough idle. A malfunctioning oxygen sensor can cause your car to be more difficult to start because it’s missing all the necessary information to decide the moment it’s appropriate to start.

There’s a possibility that the shaking you feel at idle could be caused by the oxygen sensor when it occurs in the middle of your idle or if your fuel efficiency has decreased. When the sensor for oxygen fails, it’ll provide incorrect information to the computer in your car, hindering it from being able to know whether your fuel ratio is right.

Dirty throttle body or sensor

A dirty throttle body could cause your vehicle to shake at idle because it blocks air from getting into the engine. Additionally, if there’s dirt on the exterior of the throttle plate, the engine will not receive enough oxygen, and it will be too weak or heavy.

It can cause your car to be harder to start if not enough air flows through the ignition. The best solution to solve this issue is to clean the throttle body with an aerosol cleaner so that there aren’t any limitations on airflow.

If your car has a dirty or malfunctioning sensor for the throttle, the computer in your car won’t be able to accurately determine how much you’re pressing the accelerator. The sensor will give your car’s engine an incorrect amount of fuel even though you’re not putting your foot on the accelerator, meaning it’ll run rough when it is idle. This is usually the case after oil changes because dirty oil can accumulate on this sensor, which can cause the function to fail.

Loose battery cables

If the battery cables are faulty, they won’t have enough power to start the engine. It could cause a variety of problems, like a rough idle or even stop the vehicle from running in the first place. Because you’re dealing with using an electrical circuit, all components must be secured so that power flows freely between the components. If you notice that connectors aren’t securely tightened after replacing your battery, it could be the cause of your problem.

It may also result in misfires. If your car is misfiring and is shaking at idle due to the improperly firing cylinders, do not produce enough compression to allow the engine to function efficiently. If you press the accelerator to increase the speed, this issue will disappear as it will require additional power to function properly. If you suspect that your ignition system is not functioning properly, check the spark plugs or wiring and ensure that you examine them first before replacing other components that make up your ignition.

Camshaft timing chain

If your car is equipped with an engine with a timing chain, it might have a defective tensioner of the timing chain. This component provides the force necessary to keep the camshafts firmly in place so that they do not move out of synchronization with the valves and pistons.

If this tensioner is not working properly, it could cause an unsteady idle or even stop your car from starting as it cannot be properly timed. If you’re looking to replace this component, ensure that you use only OEM components since they’ve been designed specifically for your car.

A bad crankshaft position sensor can inform the computer in your car that your engine is running however, it’s not. This could lead to all kinds of issues, including an unsteady idle or fires that don’t work. It gives the computer a precise reading of where the crankshaft is in its rotation, allowing it to adjust the timing chain in a proper way. If you discover that this sensor isn’t operating properly, be sure to replace it with an original OEM part, as remanufactured ones don’t have the right specifications for your vehicle.

The failures of these parts can also cause problems with the engine’s vacuum. A vacuum leak in the engine can result in a rough idle since there’s not enough power coming into the engine to operate properly while it idles.

The same thing can happen as misfires and may cause your car to not start when there’s too much pressure build-up inside the cylinders, and they’re not capable of releasing it after combustion starts. You’ll have to examine the hoses of your car and other components that could have cracks or other problems that may allow air to flow out of the cylinders without resistance.

How To Fix Car Vibration.

If you’re experiencing vibrations in your car, There are some things you can try to fix the issue.

In the beginning, cleanse the throttle body using an aerosol cleaner in order to get rid of any obstructions to airflow. If the throttle position sensor is faulty or dirty, it can lead to the engine in your car being rough when idle.

It is also advisable to look at your battery cable to make sure they’re secure and properly connected. If they’re not tight, it could be causing your vehicle to shake at idle.

In addition, you may be suffering from a malfunctioning tensioner for your timing chain or a sensor for the position of your crankshaft. If you suspect any of these components, be certain to replace them with authentic OEM components. In the event that you think there is a possibility of an issue with the vacuum in your engine and you suspect it, check all of the hoses of your vehicle to check for cracks or other issues. Utilizing an aerosol cleaner on the throttle body can be an option when you’re experiencing a fire and think that a gummed-up fuel injector could be the reason for it.

Make sure you do a thorough assessment of the issue prior to installing any component. So, you’ll know precisely what’s causing your vehicle to shake at idle and then be able to fix it quickly and effortlessly.

Is It Safe To Drive In A Car That Has A Rough Idle?

If your engine is suffering from a broken tensioner or timing chain, the chain or tensioner could prevent your engine from operating properly because the valves and pistons don’t function as they should. If this happens, it is best not to drive your vehicle until the issue is resolved.

In the same way, if you’ve got a leak in the engine’s vacuum, it’s important to repair it before you drive since a large enough gap could indicate that pressure builds up inside the cylinders and blocks the release of air after the combustion process begins.

In addition, problems with idling can result in misfires that may not be safe to drive by themselves. The shaking of the car while you are idling could cause problems with driving in a safe manner. When you’re having any problems with these issues, then you must get your car serviced immediately.

In the end, it’s probably better to get your car maintained prior to driving it in order to make sure that the idle problem isn’t a sign of the presence of a bigger issue.