Car Shakes When Stopped Or Idling? This is how you fix it

You expect your vehicle to start smoothly when you turn it on. You expect everything to go smoothly when your vehicle vibrates or shakes upon starting it up.

Rough idle is one of the most annoying problems. With a bit of knowledge and experience, it is possible to diagnose and fix the problem and get everything back on track in no time.

In this article, we look at some of the most common reasons for a rough idle – and what you can do to fix them. Let’s take a quick look at the most common causes:

Worn spark plugs, or vacuum leaks, are two of the main reasons why your car shakes at idle or when you stop it. This can be due to damaged or loose engine mounts, worn serpentine belts, bad fuel pumps, and other fuel-related problems.

You should first check the OBD-II scanner for trouble codes if your car shakes or vibrates at idle. If you can’t find any trouble codes or just can’t figure out what they mean, we have some possible causes here down below:

Below is a list that explains why cars vibrate when they are stopped, or idle.

7 Reasons Car vibrations or shakes when it idles

1. Wearned Spark Plugs

Wearing or damaged sparkplugs is one of the leading causes for rough idle. Spark plug wear can lead to a misfire in your engine, leading to shaking and vibrations. If you have a faulty spark plug, you should have a check engine light on your dashboard, but that doesn’t always happen.

Good news: Spark plugs are inexpensive. But, it is important to change all of them if they go bad. To prevent the problem from recurring, change spark plugs at intervals of 80,000-100,000.

2. Flexible or disconnected vacuum hoses

Your vehicle uses vacuum hoses for fuel and air systems power, regardless of whether you realize it. If these hoses are torn or disconnected, the systems won’t work the way they should, and engine performance can suffer as a result.

It’s not uncommon that when a vacuum problem gets bad enough, that the engine misfires as a result. This misfire is what you’re noticing through vibrating or shaking.

3. Broken or loose engine mounts

The motor mounts keep your engine in its place. It is likely that the motor mounts could be the issue if the engine shakes or vibrates. Inspecting your vehicle’s motor mounts can be difficult, depending on what you drive.

One easy way to check the motor mounts is to open the engine bay and have someone rev the engine while you’re looking at it. If the engine “jumps,” then you have faulty motor mounts.

Although motor mounts are quite affordable, it is possible to have them replaced with extensive labor.

4. Worn Out Belts

While there might be several belts attached to your engine, the most important are the timing and serpentine belt. Rough idle occurs when either one of these belts wears or gets damaged.

It is easier to identify and replace serpentine belts than with other types of rubber belts. Open the hood to identify the large rubber belt that runs around your engine's front. Give it a slight tug; if it feels loose at all, that’s a problem.

Check for any cracks or tears in the belt. You should replace your belt if there are any obvious signs of damage.

For timing belts, you’ll need a more comprehensive repair, but often you’ll have a check engine light letting you know about the problem.

5. Fuel Pump, Fuel Injectors/Filter Clogged or Damaged

If anything is going on with your fuel system, you’ll likely have a vibrating or shaking engine. That’s because if one of the engine’s cylinders isn’t getting enough fuel, it will throw the entire balance of the engine off.

But even if you’ve identified it as a problem with your fuel system, there are a couple of different potential culprits. Check your fuel filter first. Your fuel filter can block the flow of gasoline and cause other problems.

The next step is to check the fuel injectors and intake. You can resolve many of these problems by checking your check engine light.

6. Filter Clogs

Just like fuel is essential to your engine’s proper operation, the air is a critical component. The air filter is usually responsible for a rough idle.

Simply pull the old air filter out and check if it’s extremely dirty. This could be the problem. Try changing the filter and resetting the code to see if your problem disappears. The average cost of an air filter is $15-40, but most stores will provide replacements for no charge.

7. Faulty Camshaft Timing

A misfiring engine can be described as vibrations or shaking of the engines. Timing problems could be a reason your engine is misfiring. If you just completed significant work on your engine, this is more common, but it’s not unheard of to have timing issues if the belt or chain is worn or damaged.

If you need to replace your timing belt, it’s relatively expensive due to the labor involved.

The Mechanical Basic Breakdown

There are two main reasons that your engine might vibrate or shake while you’re idling, but the causes for these issues vary.

An engine misfire is the first problem. This occurs when your engine’s spark plug fires at the wrong time or there isn’t enough fuel or air in the combustion chamber to match the rest of the engine’s performance. You could end up replacing your engine block if you don't address this issue.

Mounting is the second problem. Your engine creates a lot of force, which is why the manufacturer mounts it to your vehicle’s frame, so it doesn’t move around. But if these mounts aren’t doing their job, your engine will shift around.

By the time you’re feeling it when you idle, the problem is severe enough that you shouldn’t drive the vehicle anywhere before it’s repaired.

Conclusion

It can be easy to overlook a slow idle while your car is running but this is not the right thing to do. You should not let this problem get out of control. It is more likely to become more severe.

Fix the issue before your engine gives up! If not, a problem that you could’ve fixed for a few hundred bucks might cost you a few thousand.