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If you have ever driven your car and all of a sudden noticed that the check engine light is flashing and shaking, then we believe you will start asking yourself why is my car shaking and check engine light on?

This article will provide you with all the relevant information on the reasons as to why this may happen, have steps to take to diagnose and fix it!

Check Engine Light Flashing And Car Shaking

A check engine light flashing and car shaking generally means your car engine is misfiring. This means that your engine is dumping unburned fuel into your car’s exhaust system. In a lot of cars, however, this does not necessarily mean serious damage to the engine.

It’s possible that the check engine light also comes up because your car is consuming fuel or releasing pollutants, but you can also continue driving with it for a long time.

At your convenience, you can then take your car to a mechanic or follow the steps provided in this article.

Flashing Check Engine Light Meaning

When your check engine light turns on, and remains still, this indicates that there is a slight error or malfunction within your engine, but it generally doesn’t mean your engine is broken beyond repair.

The error or malfunction could be as small as a loose gas cap or potentially as serious as a damaged catalytic converter. One common factor is that every driver undoubtedly dislikes seeing the check engine dashboard light come on.

However, cars undoubtedly provide many concerns for drivers in their lifetime and the check engine light blinking and car shaking is one of them. In most cases, the check engine light on your dashboard will flash when you’re accelerating at high speed.

If the check engine light begins to flash continuously instead of a more steady appearance, this will often represent a more severe issue that you can prevent. In this instance, you better take the car to a mechanic as soon as possible.

All cars will have different sensors and actuators that work to detect any forms of malfunctioning and then register this info on your car’s computer system.

The engine control unit will constantly monitor all these sensors in the car while you are driving. They do tasks like calculating how much fuel should be in the engine at any given time and at which area should the ignition be fired.

If the values from a sensor become faulty at any given time, a trouble code will be triggered. Once the engine control unit receives the wrong values from the sensor various times, the check engine light will light up on your dashboard, indicating a problem.

Note: if a more severe problem occurs like a misfire, the check engine light will begin to flash. This indicates that there is a problem that may damage the catalytic converter and you must act now.

Different Types of Check Engine Light Flashes

When your check engine light on and car shaking, it may be difficult to immediately diagnose what is happening. However, there are 3 types of flashes that will depict the severity of your issue, so these are very important to know:

  • Steady light
  • Intermittent flashing
  • Continuous flashing


The Steady Engine Light

If the engine light is just on and has a steady light that is not flashing, it means there is no significant issue in your car. The resulting fixes should be quick and inexpensive.

Note: In some cases, the engine light may initially flash and then become stable.

The intermittent flashing

If the check engine light flashes for a little while, and then turns off by itself; this simply means there is a light failure. This could be anything such as a broken wire that keeps connecting and disconnecting, causing the check engine light to turn on and off accordingly.

The continuous flashing

If the check engine light is flashing continuously, this is because there is an emergency. Therefore, you should immediately stop the vehicle and call to get the car towed to a garage for inspection by a professional mechanic.

It’s important to note that the engine control unit will store a fault code related to the malfunction whenever the light flashes. So, if you have an On-Board-Diagnostics OBD2 scan tool, you will be able to read and interpret the fault code.

Why is My Check Engine Light Flashing and Car Shaking

The car’s check engine light is also referred to as the malfunction indicator light (MIL), which in other words, is a warning light that indicates there is some form of malfunction with your car.

The light will be triggered anytime something goes wrong in your vehicle. As you already know, it’s a flashing light that displays on your dashboard with the symbol of an engine.

Some of the most common reasons for the check engine light flashing and car shaking are:

  • Faulty fuel cap
  • Failing catalytic converter
  • Faulty ignition coil
  • Faulty spark plugs
  • Faulty bad mass airflow (MAF) sensor
  • Faulty oxygen sensor
  • Faulty charging system

Faulty Fuel Cap

As you may already know, a faulty, cracked, or loose fuel cap can lead to the engine light flashing due to the fuel system having a vapour leak. However, it could sometimes be a more severe leakage in your car fuel system’s upper portion.

If this occurs, you should tighten or replace the fuel cap and then continue to drive. After driving your car for a short period of time, the check engine light should go off. If it doesn’t, then I recommend taking the car to your mechanic to investigate.

Failing Catalytic Converter

The catalytic converter controls your car’s exhaust system. It basically converts carbon monoxide and other harmful gases into less toxic byproducts.

If your catalytic converter starts failing, your car’s performance will be affected and you’ll be forced to spend more money on fuel. Replacing a catalytic converter can be very expensive; typically costing around £300-£800 each.

If the catalytic converter is the cause of your car’s check engine light flashing and car shaking, it’s important to see a mechanic immediately.

Faulty Ignition Coil

The car ignition coil is part of your vehicle’s ignition system, where it inducts the coil by converting a car’s voltage system to the needed volts to trigger the spark plug and then ignite the engine’s air-fuel mixture.

If the ignition coil burns out or shorts the check engine light will turn on. In this scenario, it is best to have the entire vehicle’s ignition system checked.

Faulty Spark Plugs

It’s very common for drivers to not replace their vehicle’s spark plugs as advised in their car manual’s maintenance schedule. Failing spark plugs can cause the check engine light and you will be required to change them as soon as possible.

Faulty Bad Mass Airflow (MAF) Sensor

Your car’s Mass Airflow Sensor, also known as MAF Sensor, helps the car’s computer to determine the amount of fuel that is to be added based on the amount of air that enters the motor.

If there is a dirty air filter or an improper installation, then one of the MAF sensors is likely to fail. However, a failing MAF sensor is not an emergency. However, you will experience a decrease in fuel economy, along with your vehicle losing performance if you don’t fix it.

You will require a professional mechanic to fix a failing mass airflow sensor due to the car’s air intake system’s technicality.


Faulty Oxygen Sensor

A car’s oxygen sensor measures the amount of oxygen in the car exhaust system. It will communicate this information to your vehicle’s computer to allow for the adjustment of the engine’s air and fuel mixture.

So, any time your oxygen sensor is faulty, the vehicle will use up more fuel than it should and produce more emissions. This is not an alarming issue, but you should make sure to get a mechanic to fix it as soon as possible.


Fixing the Check Engine Light flashing and car shaking

It’s important to understand that you may require a professional to fix most of these check engine light flashing and car shaking related issues.

For those who don’t have any experience working on cars or do not know how to use simple tools, please do not attempt this alone. Get someone with experience who can help you to minimise any potential accidental injury or damage.

Here are some general steps to fixing engine light on car shaking:

1. Get an OBD Reader

Once you obtain and plug in the reader, it will help to display the code the computer has recorded. Remember that these codes are generic diagnostic codes and not specific to a model of car.

When purchasing an OBD reader, you should be able to get one at an auto spare parts store near you. Otherwise, you will be able to source one online.

Here’s an example of an On-Board-Diagnostics OBD2 scan tool readily available on Amazon:

As an Amazon Associate I earn from qualifying purchases

2. Scan For Codes

You should always pay attention to the way your cars perform, and I’m sure you already do. However, suppose your vehicle has an emissions problem, you may not notice a change in performance.

Knowing what symptoms your car is having will help you understand the problem more precisely. Look under the lower edge of the driver’s side dashboard, where you should see a trapezoid-shaped port for the reader.

Make sure the engine and ignition are off before plugging the reader in. Once connected, turn the key a little to turn the ignition on but not the engine.

Press the scan button and then wait for the reader to respond. Shortly, it will display the codes stored within the computer. Write down the codes.

3. Search For Your Code

I recommended then searching the internet for information on your code, there will be lots of forums and threads which may provide information on people who have fixed it and written about it.

In addition, the OBD website should be able to help you. Here, you will be able to find out what your code means. What you should do is search the code along with your vehicle and its model.

4. Search the Part, Remove and Change It.

For example, search for the purge valve if this is the part you need. Searching online is the easiest way to pick out the part if you cannot reach your local auto parts store.

5. Erasing The Code

Once you have changed the necessary parts, you should plug the OBD reader back in, and then press and hold the erase button.

After the screen changes, press the button again to confirm. After that, the code will go off, and then the check engine light should go off. Problem resolved!


FAQs (Frequently Asked Questions)

Can I drive my car with the check engine light blinking?

If the check engine light flashes for a little while, and then turns off by itself; this simply means there is a light failure like a broken wire. If the check engine light is flashing continuously, this is because there is an emergency and should immediately stop the vehicle and get an inspection by a professional mechanic.

Why is my car shaking and misfiring?

If your car is shaking and misfiring that your engine is dumping unburned fuel into your car’s exhaust system. This indicates that there is a problem that may damage the catalytic converter and you must act now. However, with some cars, this does not necessarily mean serious damage to the engine.

Please leave a comment below if you have a question regarding check engine light flashing and car shaking!

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