What Causes a Car to Sputter While Driving? (Do This Now)

what causes a car to sputter while driving

A sputtering car engine can be a cause for concern as it indicates an underlying issue that needs attention. A car that sputters while driving can be frustrating and even dangerous, as it may lead to a loss of power while driving.

This article will explore the various factors that can cause a car engine to sputter and provide some guidance on how to address these issues.

1. Faulty Spark Plugs

One of the most common causes of a sputtering engine is faulty spark plugs. Spark plugs play a vital role in providing the necessary ignition for the air-fuel mixture in the combustion chamber. Over time, spark plugs can wear out and lose their ability to function properly, leading to unburnt fuel, misfires, and a sputtering engine.

To address this issue, it is essential to inspect and replace your spark plugs regularly. If you haven’t replaced them according to the manufacturer’s recommended schedule, it may be time to do so. Additionally, consider checking the ignition coils, as they could also cause similar issues.

2. Clogged Fuel Filter

Another common cause of engine sputtering is a clogged fuel filter. The fuel filter is responsible for filtering the fuel going to the fuel injectors before entering the engine. A clogged fuel filter can result in low fuel pressure or even clogged fuel injectors, leading to a lean-running engine and sputtering.

To prevent this issue, ensure that the fuel filter is replaced according to the manufacturer’s recommended schedule. Fuel filters are generally inexpensive and straightforward to replace.

3. Faulty Fuel Pump

A faulty fuel pump can also cause a sputtering engine, as it may result in low fuel pressure. The fuel pump is responsible for delivering fuel from the tank to the engine, and if it is not functioning correctly, the engine may not receive enough fuel to run smoothly.

To diagnose a faulty fuel pump, you can install a temporary manual fuel pressure gauge to the fuel pressure rail and check the fuel pressure at idle and while revving the engine. If the fuel pressure is too low, there may be an issue with either the fuel filter or the fuel pump.

4. Vacuum or Intake Leak

A vacuum or intake leak can cause a sputtering engine, as it may result in a lean air-fuel mixture. Leaks around the intake manifold or in the hoses connected to the intake manifold can cause the engine to run lean, leading to sputtering.

To find a leak, you can use an EVAP smoke machine or listen for high-pitched noises around the engine bay while the engine idles. Alternatively, you can spray soap around the intake hoses to detect any leaks visually.

Read also >> Engine Sputtering: When Starting, Accelerating (Fixed)

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5. Dirty or Damaged Mass Airflow Sensor

The mass airflow sensor plays a crucial role in ensuring the correct amount of air is supplied to the combustion chambers. When the sensor becomes saturated with dirt particles, it can no longer provide accurate information to the engine control unit (ECU), resulting in an incorrect air-fuel mixture and a sputtering engine.

To resolve this issue, you can remove and clean the mass airflow sensor using an electronic cleaner.

6. Dirty Fuel Injectors

Fuel injectors are responsible for spraying fuel into the combustion chambers, where it mixes with air and is ignited by the spark plugs. Over time, the small filters inside the fuel injectors can become clogged, leading to insufficient fuel delivery and a sputtering engine.

To address this issue, you can have the filters inside the fuel injectors replaced by a professional mechanic.

7. Faulty Catalytic Converter

A faulty catalytic converter can cause a sputtering engine, as it is responsible for converting harmful exhaust gases into less harmful emissions.

A clogged or damaged catalytic converter can result in increased backpressure in the exhaust system, leading to engine sputtering.

To diagnose a faulty catalytic converter, you can use a catalytic converter cleaner or look for signs such as a strong smell of rotten eggs.

8. Faulty Oxygen Sensors

Oxygen sensors play a critical role in regulating the amount of fuel entering the combustion chambers. Over time, these sensors can become contaminated with dirt and lose their ability to provide accurate information to the ECU. This can lead to either a rich or lean air-fuel mixture, resulting in a sputtering engine.

To diagnose faulty oxygen sensors, you will need a diagnostic scanner to read the sensors’ data and determine if they are functioning correctly.

9. Exhaust Manifold Issues

The exhaust manifold is responsible for handling the engine’s scorching exhaust gases. If the exhaust manifold is leaking, the engine can sputter and overheat. You might also hear hissing or tapping sounds, particularly when the engine is cold, indicating exhaust gas escaping from the manifold.

In this case, it is essential to have the exhaust manifold inspected and repaired by a professional mechanic to prevent further damage to your engine.

10. Issues with Gaskets and Seals

An exhaust or vacuum leak in the engine can also lead to a sputtering engine. Worn or damaged gaskets and seals can cause leaks that result in sputtering and may damage more expensive engine components if not addressed promptly.

To prevent further damage and resolve the issue, it is essential to replace any worn or damaged gaskets and seals as soon as possible.

7 Reasons Why Your Car Engine Is Sputtering >> Check out the video below:


A sputtering car engine can be caused by various factors, including faulty spark plugs, clogged fuel filters, and issues with the fuel system.

To ensure your vehicle runs smoothly and safely, it is crucial to address these issues as soon as they arise. Regular maintenance, such as replacing spark plugs and fuel filters according to the manufacturer’s recommended schedule, can help prevent many of these problems.

If you are unsure about the cause of your car’s sputtering engine or need assistance in diagnosing and repairing the issue, it is always best to consult a professional mechanic.

They can help you identify and fix the problem, ensuring your vehicle runs smoothly and safely on the road.

Steve P.

Steve is an automotive technician, technical writer, and Managing Editor. He has held a lifelong passion for cars, with a particular interest in cars like the Buick Riviera. Steve is based in Boise, Idaho.

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