Car Shakes When Accelerating but Not When Coasting (Solved)

There are several instances where motorists experience car shakes when accelerating but not when coasting. This can result in some uncomfortable situations and disappointments.

However, even though some causes are more obvious than others, you might find it hard to discover the exact reason why your car shakes when accelerating but not when coasting without help from an experienced mechanic.

In this article, we’ll explain some of the possible reasons why your car shakes when accelerating but not when coasting and how to go about fixing this problem.

Let’s get started.

1. Bad CV Joints

A bad cv joint is one of the main reasons why a car shakes when accelerating but not when coasting. Typical misconceptions about CV joints are that they are only used to connect the transmission to the axle.

However, this notion is almost untrue because CV joints play a crucial role in allowing rotation and stopping movement along the shaft axis.

This can be achieved by aligning a cross-shaped inner CV with a flat outer CV. So if the CV joints become faulty, it could be the reason why a car shakes when accelerating but not when coasting.

2. Wheel Bearing Failure or Loose Bearings

Loose or failing wheel bearing is another major reason why a car shakes when accelerating but not when coasting.

Sadly, it can be tricky to identify since many people do not realize this problem until it is too late to deal with them.

The function of a wheel bearing is to enhance the wheel’s rotation and ensure the wheel remains aligned with its axis.

However, bearings can encounter cracks that’ll make them move out of their axis, and this could cause the car to shake.

Related: Wheel Bearing Replacement Cost

3. A Worn-Out Engine Mount

Engine mounts that are worn out are another reason why a car shakes when accelerating but not when coasting.

Engine mounts perform a crucial function in separating the engine from its frame and disconnecting other components from vibrations.

Engine mounts can last between 5 and 7 years before they need replacing. A worn-out engine mount can cause your vehicle to shake, rattle, and squeak whenever you accelerate.

4. Loose Lug Nuts

Lug nuts are essential components of wheel studs and your suspension system. They are of various shapes and sizes, but their primary role is to tighten a wheel’s hub linked to the axle.

Most times, a good number of these lug nuts tend to get very loose, while others might not be adequately tightened.

If they are not tightened correctly, it is a reason why a car shakes when accelerating but not when coasting.

5. Vacuum Leak

A vacuum leak can also be a reason why a car shakes when accelerating but not when coasting. When there’s a leak in a vacuum, it means there could be a cracked intake hose or a bad intake manifold gasket.

6. Unbalanced Tires

When you have unstable tires, your vehicle may shake during acceleration. Unbalanced tires are a result of uneven wear.

There could also be a problem with the tire pressure. Also, uneven tire treads can result in vibrations that will cause shakes during acceleration or turning.

7. Bent Axle

Another common reason why a car shakes when accelerating but not when coasting is a bent axle. This can be addressed by a professional mechanic who will have the axle straightened.

However, after doing all this, there’s a need to check still if there’s another bend since it can sometimes feature arcs that can only be seen at certain angles.

8. Worn-Out Clutch

A worn-out clutch can also make your car shakes when accelerating but not when coasting.

This is a prevalent problem even if many people fail to notice that the reason for their car shakes is a worn-out clutch or worn-out pressure plate.

A worn-out pressure plate will fail to transmit the ideal torque amount to the flywheel, thereby making you rev up more often than usual during acceleration and turning. If you have a worn-out clutch, it can result in severe vehicle shakes.

9. Faulty Brake Calipers

If your brake calipers are faulty, it can result in car shakes when accelerating but not when coasting.

Once your brake calipers stop functioning as they should, they can no longer prevent your car from rolling, thus causing the wheels’ erratic movements, thereby making your car shake.

10. Bad Struts or Shocks

If your struts or shocks have any form of a break or even a crack, which is a common occurrence in a car, it can cause your car to shake when accelerating but not when coasting.

Related: Car Shakes When Braking (Why & How To Fix)

How to Fix Car Shakes When Accelerating but Not When Coasting

After knowing some of the reasons why a car shakes when accelerating but not when coasting, Here are some solutions to these problems.

Keep in mind that you need to see to the repair of these problems so that your car can function properly again.

You can fix some problems yourself, while others require the services of a professional mechanic.

1. Fixing Unbalanced Tires

If the reason why your car shakes when accelerating but not when coasting is unbalanced tires, you’ll require a jack, a screwdriver, and a lug wrench. The following processes are required to fix it;

1. The first step is to get rid of the tire weights.
2. After removing the tire weights, you can proceed to remove the tires.
3. Make sure the tire is as clean as possible.
4. Once it is spotless, you can now fix them back in their proper positions and install the weight to its normal state.
5. Inspect the wheels as often as possible to make sure you have rightly adjusted the wheels.
6. The last process is to get the tires back into their rightful position.

2. Replacing Bad CV Joints

If you want to repair a car that shakes when accelerating but not when coasting due to bad CV joints, you must disconnect the driveshaft and study the movements of the joints.

Examine the lubrication within the joints to check whether there’s any rustic contact or insufficient grease. If you notice any of these factors, it’s time to change the CV joints.

Take your car to an experienced mechanic to change your vehicle’s CV joints, or click here to check out our guide on how to do it yourself.

3. Replacing Bad Spark Plugs

If the reason why your car shakes when accelerating but not when coasting are bad spark plugs, then the following is what you must do;

Firstly, locate where the spark plugs are. After locating them, disconnect them and have them replaced with new ones. Also Ensure that you are making use of suitable plugs.

Related: Spark Plug Replacement Cost

4. Fixing Low Lubrication

If you fail to give your car parts the right amount of lubricant, they could malfunction and cause friction.

Therefore, you must inspect the fluid level of your transmission and replace it if necessary. However, you have to fix certain things to ensure complete resolution to the problems of your car.

Here ‘s what to do

1. Make sure you frequently switch off your car when changing your oil or fluid.
2. Ensure the liquid you are using is the right one for your engine. For verification, go through your car owner’s manual.
3. Avoid pouring excessive fluid.
4. As soon as you finish pouring the fluid, start the engine for about one minute or two to enable the fluid to circulate the parts.

5. Fixing Other Causes

Suppose you want to fix other issues such as the broken axle, brake caliper, etc.

If so, you will need the assistance of experienced personnel or mechanics since these are the kinds of problems that require a lot of technical knowledge and are time-consuming.

So, if you’re not a professional or have the required knowledge, take your car to a mechanic for repairs.

Frequently Asked Questions

Conclusion – Car Shakes When Accelerating but Not When Coasting

There is no effect without a cause. Therefore, something must have happened before you experience car shakes when accelerating but not when coasting.

It could be that you have faulty CV joints, worn wheel bearings, worn engine installations, loose faulty vacuum leaks, unbalanced tires, and bent axles, amongst others.

It is crucial that whenever the vibration occurs, and it happens to be any one of the above causes, you should seek a possible solution as soon as possible to prevent further disastrous consequences that might endanger your life and that of your passenger(s).