Engine Check Engine Light Troubleshoot

Troubleshooting Guide: Why Your Car Sputters When the Check Engine Light Is On

Check engine light car sputtering

There are many reasons why your car’s engine might be sputtering with a check engine light. Some of the most common causes of engine sputtering include a dirty mass airflow sensor, failing spark plugs, a bad fuel filter, or issues with the fuel system.

It’s also possible that your car is simply running low on gas, so it’s worth check your fuel gauge before assuming that there’s a more serious cause.

Why Is My Car Sputtering With A Check Engine Light On

When the check engine light comes on and your car begins to sputter, it is a sign that something is wrong with your vehicle’s engine.

The check engine light is a warning system that is built into your car’s ECU and it is triggered when the ECU detects a problem with the engine.

It is designed to alert you to potential problems with your car’s engine, transmission, or emissions systems.

A very common cause of engine problems such as sputtering is a problem with the spark plugs.

If they are worn or damaged, they may not be able to create the spark needed to ignite the fuel. This can cause your car to sputter or hesitate when you accelerate.

Here are some more causes in more detail:

1. Fuel System Issues

One of the most common causes of engine sputtering is a problem with the fuel system. A clogged fuel filter or dirty fuel injectors can restrict the flow of fuel to the engine, leading to a sputtering engine. A faulty fuel pump can also cause sputtering, as it may not be delivering enough fuel to the engine.

Another issue that can cause sputtering is contaminated fuel. Water or debris in the fuel can cause the engine to run poorly. It is important to regularly check and replace the fuel filter and use high-quality fuel to prevent these issues from occurring.

2. Faulty Spark Plugs

Spark plugs are responsible for igniting the fuel in the engine. If the spark plugs are worn or damaged, they may not be able to ignite the fuel properly, leading to sputtering. Over time, spark plugs can become fouled with carbon deposits, reducing their effectiveness.

a bad spark plug
Cleaning a dirty spark plug

Replacing the spark plugs at regular intervals can help prevent sputtering caused by faulty spark plugs. It is also important to use the correct type of spark plugs for your vehicle, as using the wrong type can cause issues.

3. Bad Oxygen Sensor

The oxygen sensor is responsible for monitoring the amount of oxygen in the exhaust system and adjusting the air to fuel ratio depending on how much oxygen it detects.

If the oxygen sensor is faulty, it may not be able to provide accurate readings, and this can cause the engine to run rich or lean which can lead to sputtering. A bad oxygen sensor will usually also cause the check engine light to come on.

Replacing a worn oxygen sensor can help fix sputtering and can also improve fuel efficiency.

bad oxygen sensor car sputtering
Oxygen sensor in the exhaust pipe

4. Ignition Coil Failure

A bad ignition coil can cause engine sputtering and a check engine light. The ignition coil is responsible for providing the spark that ignites the air-fuel mixture in the engine’s combustion chamber.

If the ignition coil is not functioning properly, it can cause a misfire in one or more cylinders, leading to engine sputtering or rough running. Ignition coil failure is not very common but it can be caused by age, excessive engine heat, or engine vibration.

5. EGR Valve Malfunction

A bad EGR valve can cause engine sputtering. The EGR valve is responsible for recirculating a portion of the engine’s exhaust gases back into the combustion chamber to help reduce harmful emissions.

If the EGR valve is not functioning properly, it can cause a variety of issues with the engine, including sputtering or misfiring. A clogged or malfunctioning EGR valve can disrupt the air to fuel ratio in the engine, leading to engine performance issues such as a reduction in power and fuel efficiency. The vehicle may also stall or hesitate while accelerating.

6. Vacuum Leaks

A vacuum leak occurs when there is an opening in the vacuum system, allowing air to enter the engine without being properly measured by the mass airflow sensor. This can cause the engine to run poorly, leading to sputtering.

Vacuum leaks can be caused by a cracked or damaged vacuum hose, a faulty intake manifold gasket, or a faulty brake booster.

7. Dirty Air Filter

A dirty air filter can cause engine sputtering and the check engine light to stay on. The air filter is responsible for preventing dirt, debris, and other contaminants from entering the engine’s combustion chamber.

When the air filter becomes dirty or clogged, it can restrict the flow of air to the engine, leading to a lean air-fuel mixture. This can cause the engine to sputter or hesitate, especially during acceleration or when under load.

Symptoms of Check Engine Light and Car Sputtering

When your check engine light comes on and your car starts sputtering, it can be a sign of a serious problem. Here are some of the symptoms you may experience:

  1. Check engine light on: The check engine light is a warning sign that something is wrong with your vehicle’s engine. If the light is on and your car is sputtering or jerking, this may indicate a serious issue that needs to be addressed immediately.
  2. Car jerking or sputtering while driving: If your car is sputtering or jerking while you’re driving, this may indicate a misfire in the engine. This can be caused by a variety of issues, such as faulty spark plugs, ignition coils, or fuel injectors.
  3. Decreased acceleration or power: If your car is struggling to accelerate or has decreased power, this may be a sign of a more serious issue with the engine. This can be caused by a variety of issues, such as a clogged air filter, malfunctioning fuel injectors, or a faulty oxygen sensor.
  4. Rough idling or stalling: If your car is idling roughly or stalling, this may be a sign of a problem with the engine’s combustion process. This can be caused by a variety of issues, such as a faulty EGR valve, vacuum leaks, or a malfunctioning oxygen sensor.
  5. Poor fuel economy: If you notice a sudden decrease in your car’s fuel economy, this may be a sign of a problem with the engine. This can be caused by a variety of issues, such as a clogged air filter, malfunctioning fuel injectors, or a faulty oxygen sensor. If you notice a sudden decrease in fuel economy, it’s important to have your car inspected by a professional mechanic to identify and address the issue.

What Next – Diagnosing And Fixing A Check Engine Light with Car Sputtering

When trying to fix check engine light and car sputtering, it’s important to ask the right questions to diagnose and address the issue properly. Here are some questions to ask:

  1. When did the check engine light come on? Knowing when the check engine light came on can help you identify what may have caused the issue.
  2. Does the car sputter or jerk at certain speeds or during certain driving conditions? Understanding when the car sputters or jerks can help you identify what may be causing the issue.
  3. Have you noticed any other symptoms, such as decreased acceleration or power, rough idling, or poor fuel economy? These symptoms can help you identify what may be causing the issue.
  4. Have you noticed any strange smells or sounds coming from the engine? Strange smells or sounds can be a sign of a more serious issue with the engine.
  5. Have you had the car inspected recently? If so, what were the results? Knowing what was inspected and the results of the inspection can help you narrow down what may be causing the issue.

Here are some things to take a look at that may help to fix your car if it’s sputtering and the check engine light is staying on.

1. Check The Fuel System

One of the most common causes of a check engine light and car sputtering is an issue with the fuel system. To check the fuel system of a car, begin by checking the fuel level (make sure there’s gas in the tank!) and making sure the fuel cap is tightly secured.

You should also inspect the fuel lines and connections for any signs of damage or leaks. You can also check the fuel pump by listening for a humming sound when you turn the ignition to the “on” position (without starting the engine). If you don’t hear a sound, the fuel pump may be faulty and need to be replaced.

You can also use a fuel pressure gauge to check the fuel pressure and make sure it’s within the manufacturer’s specifications.

It’s also worth checking the fuel filter to make sure it’s not clogged or dirty, and replace it if your car has a replaceable filter.

You can also try using a fuel system cleaner to clean out any debris that may be causing the issue.

2. Check The Ignition System

Another possible cause of a check engine light and car sputtering is an issue with the ignition system.

Remove and check each spark plug to ensure they are clean and not damaged or worn out. Test each plug using a spark plug tester to check for spark, and use a multimeter to test the resistance of each ignition coil. If the coil, distributor cap, or rotor are worn or damaged, they may need to be replaced.

The timing should also be checked using a timing light. Issues with the timing can be complicated and you may need to bring the car to a mechanic if the timing is off.

3. Exhaust System Issues

To check the exhaust system of a car, start by visually inspecting the exhaust pipes, muffler, and catalytic converter for any signs of damage, such as rust or holes.

If you find any damage, it should be repaired. Next, start the engine and listen for any unusual noises, such as rattling or hissing, which could indicate a problem with the exhaust system.

You can also use a flashlight to check for any smoke or fumes coming from the exhaust pipes. If you notice any excessive smoke or fumes, it could be a sign of a problem with the engine or exhaust system.

If you have access to one, you should use a gas analyzer to check the emissions coming from the tailpipe and make sure they are within the legal limits.

About the author

The Motor Guy

The Motor Guy is a passionate car enthusiast with a love for troubleshooting and diagnosing all sorts of vehicle problems.

With years of experience in OBD diagnostics, he has become an expert in identifying and solving complex automotive issues.

Through TheMotorGuy.com, he shares his knowledge and expertise with others, providing valuable insights and tips on how to keep your vehicle running smoothly.

Qualifications:
- 12 years experience in the automotive industry
- ASE Master Automobile Technician
- A Series: Automobile and Light Truck Certification, A9 Light Vehicle Diesel Engine Certification
- Bachelor's Degree in Information Systems

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  • Does having a malfunctioning oxygen sensor cause greater harm if not fixed immediately, such as damaging the catalytic converter or the engine itself?