Car Shakes When Idle and Accelerating

Car Shakes When Idle and Accelerating

If your car shakes when idle and accelerating and you don’t live in an earthquake-prone area, it’s time to contact your mechanic.

Usually, an internal combustion engine should have vibrations and noise due to moving parts. But the vibrations shouldn’t be too much to cause discomfort behind the wheel.

Your car is one of the assets with its special place in your heart. It takes you to work, road trips, for a track race, and finally back home. It has multiple systems and components that rotate.

Car parts need regular maintenance like lubrication and greasing. On the other hand, electrical components help you interact with the car through the dashboard. They, too, need maintenance.

What to Do if Your Car Shakes When Idle and Accelerating
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What to Do if Your Car Shakes When Idle and Accelerating

The first step to take if your car shakes when you start the engine is troubleshooting the problem. Note some causes may be minor that you can fix yourself.

Simple do-it-yourself tasks may save you some coins.

However, if the problem is complex, you need to call a specialist to help you. Here are the possible causes of your car vibrations.

1. Loose Engine Mounts

The engine mounts are attached to the car frame to hold the engine firmly. They are well designed with mechanisms to absorb most of the vibrations from the engine to keep the vehicle calm.

Although the mounts may not absorb all the vibrations from the internal combustion engine, they minimize them.

Loose engine mounts aren’t able to effectively absorb the vibrations. The results are extreme shaking of the whole vehicle.

Usually, the front end of car shakes when accelerating. You may feel like earth trembling tremor has occurred.

2. Worn Out Spark Plugs

Spark plugs are part of the electrical components in the car. They are fixed within the combustion chamber to ignite the injected fuel-air mixture.

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Upon fuel ignition, the explosions happen, forcing the pistons to rotate the crankshaft and produce power.

The system is controlled by the Engine Control Module (ECM) that receives data from various sensors.

The ECM determines the amount of fuel-air mixture injected into the combustion chamber. But if the spark plugs are faulty, they won’t ignite the mixture to complete the combustion.

As a result, the engine will shake due to inconsistent timing, and at some point, you may hear engine misfire sounds.

Read: Airbag sensor on dashboard

3. A Worn-Out Timing Belt

A timing belt connects the crankshaft and the camshafts by pulleys. Inside the belt cover, a sensor monitors the speed of the spinning pulley teeth and sends data to the ECM.

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The data determines the amount of fuel and oxygen injected into the combustion chamber.

If the timing belt wears, the sensor will send inaccurate information. Inappropriate fuel-oxygen mixture injected will lead to incomplete combustion.

If you experience engine shaking and loss of power, it’s time to troubleshoot your timing belt.

4. Faulty Fuel System

The fuel system contains several components fixed from the tank to the combustion chamber. It consists of;

  • The fuel line
  • Fuel filter
  • Fuel pump
  • Fuel injectors

Car fuel may contain some sediment that blocks the fuel pipes. It’s for this reason the system is equipped with a fuel filter.

The sediments may also block the fuel pump or clog the fuel filter. On the other hand, carbon from the combustion chamber may block the fuel injectors. The injectors have small nozzles that release fuel to the combustion chamber.

In all the above cases, incorrect amounts of fuel may be injected into the combustion chamber. This leads to misfiring. You may also notice the car struggles to accelerate and shakes when idle.

5. Clogged Air Filter

The air filter filters dust and debris as clean air enters the engine. That’s the purpose of the air filter.

However, an air filter may be clogged with dust after some time. This results in less amount of air getting into the engine.

An imbalance fuel-air mixture will be injected into the combustion chamber. Once ignited, incomplete combustion happens due to insufficient oxygen.

Usually, you’ll smell unburned fuel from the tailpipe, and the engine will shake.

6. Faulty Oxygen Sensor

An oxygen sensor determines the ratio of air to be mixed with the fuel. Due to exposure to engine heat, age, and carbon build-up, the oxygen sensor may wear out with time.

Unfortunately, after failing, it sends inaccurate information to the ECM. The ECM determines the wrong oxygen-fuel ratio, and as usual, incomplete combustion happens.

If your car vibrates when idle and AC is on, you’re just overworking the engine. It’s a clear sign the engine is producing very low power.

You may also smell unburned fuel or misfiring.

7. Loose or Disconnected Vacuum Hoses

Modern cars have vacuum hoses that power air and fuel systems. If the pipes are loose or disconnected, the system cannot determine the fuel and air ratio.

As a result, the engine will have extreme vibrations and poor gas mileage.

FAQs on Car Shakes

Will a Bad Transmission Cause a Car to Shake?

Automatic transmission fluid can mess up your ride if it’s unchecked. Low automatic transmission fluid will cause engine vibrations and delay in gear shifting.

To keep your car running smoothly, carry out regular preventive maintenance by checking at the following;

Engine oil and oil filter
Transmission fluid
Air filter
Spark plugs
The fuel system
Tire pressure

Ensure your car is regularly inspected by a specialist to avoid troubles during your trips.

What Are the Signs that Your Transmission is Going Out?

Delay in gear shifting
Leaking transmission fluid
Burning smell
Grinding noise

Can a Bad Alternator Cause Engine to Shake?

A car alternator produces power to recharge the battery and ignite the fuel in the combustion chamber using spark plugs.

If the alternator is faulty, the spark plugs will misfire, shaking the engine.

Read: How to clean dried urine from car seat

If your car shakes when idle or accelerating, know there are several reasons behind it. Especially for a modern car, you’d better call a specialist to troubleshoot it. 

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