If you’re asking “What causes a car to sputter while driving?”, you might be on the side of the road or might have noticed this sign when you’re on the road. There are different reasons why this might be the case, so it’s important to troubleshoot the problem.
In some cases, ignoring a sputtering sound while driving your car can lead to engine damage, so it’s important to address it quickly. With that in mind, let’s take a look at this complete guide on what causes engine sputtering in a car.
JUMP TO TOPIC
- 1 A List Of Reasons Why Your Car is Sputtering While Driving
- 1.1 1. Out of Gas
- 1.2
- 1.3 2. Clogged or Faulty Fuel System
- 1.4 3. Clogged Catalytic Converter
- 1.5 4. Faulty MAF Sensor
- 1.6 5. Malfunctioning ECU
- 1.7 6. Faulty Oxygen Sensor
- 1.8 7. Worn Out or Faulty Spark Plugs
- 1.9 8. Worn Out Gaskets or Seals
- 1.10 9. Intake Manifold Leak
- 1.11 10. Damaged Fuel Pump
- 1.12
- 2 Conclusion
A List Of Reasons Why Your Car is Sputtering While Driving
If there is nothing wrong with your car, your engine is probably sputtering because you’re out of gas. Here are 10 reasons why you have a shuddering car while driving. It’s a good idea to check them and fix what you can or contact a mechanic for help.
1. Out of Gas
| Main Sign | The car engine is sputtering or the fuel gauge is low |
| How to Test | Check the fuel gauge. |
| Do You Need a Mechanic? | No |
| How to Fix It | Fill up the tank |
The main reason why the engine sputters when you’re driving is because you’ve run out of gas. When the engine isn’t getting enough fuel, it will struggle, and before you know it, the car will stop running completely. This reason is expected if you didn’t fill your car up earlier, so there’s no need to panic.
2. Clogged or Faulty Fuel System
| Main Sign |
|
| How to Test | Inspect the fuel system, and use an OBD2 scanner. |
| Do You Need a Mechanic? | If you are not handy with tools |
| How to Fix It |
|
Another reason why your car might be sputtering when driving is a faulty or clogged fuel system. The clogged system can cause a lean fuel mixture in the combustion chamber because it restricts the delivery of fuel.
Your fuel filter or fuel lines might be clogged, or the fuel injectors might be the problem. Depending on what is clogged, you can clean the fuel system or replace the fuel or air filters or the dirty fuel injectors. You can also contact a mechanic if you are not good with tools.
3. Clogged Catalytic Converter
| Main Sign |
|
| How to Test | Use a back pressure gauge, and inspect the converter. |
| Do You Need a Mechanic? | If you are not handy with tools |
| How to Fix It |
|
Also, the catalytic converter can become clogged, and it will make the engine shudder. The main reason why a blocked converter can cause a sputtering car engine is that it blocks the exhaust smoke from coming out of the tailpipe. This means that the exhaust builds up in the combustion chamber.
The clogged converter will affect your engine performance and slow down the acceleration performance. This will cause the engine to sputter constantly. You need to remove the converter to use a pressure washer to clean it, so if you are not sure about using tools, it’s best to contact a mechanic.
4. Faulty MAF Sensor
| Main Sign |
|
| How to Test | Use an electrical connector. |
| Do You Need a Mechanic? | If you are not handy with tools |
| How to Fix It |
|
You might also be dealing with a damaged or dirty mass airflow sensor which causes the car to sputter when you’re driving. You need a balanced mix of fuel and air in the combustion chamber, and the mass airflow sensors are used to check that the chamber is getting the right amount of air.
When there are dirt particles clogging the sensor, it stops them from transmitting the correct information to the ECU. The engine will sputter because of the wrong combination of air and fuel. The MAF sensor can be cleaned with an electronic cleaner, but you need to remove it. You can also replace it if it’s completely damaged or contact a mechanic.
5. Malfunctioning ECU
| Main Sign |
|
| How to Test | ECU simulator
Diagnostic scanner |
| Do You Need a Mechanic? | Yes |
| How to Fix It | Repair or replace the ECU |
The ECU is the engine control unit or engine control module, and it is the main computer chip of the vehicle. It controls when the spark plugs fire and how much air and fuel are in the combustion chamber.
If the ECU is malfunctioning, it can affect the fuel mixture or the spark plugs misfiring, making your engine sputter. The best thing to do is to repair or replace the ECU, and a mechanic can best do this for you. Repairs should cost up to $750, depending on the mechanic.
6. Faulty Oxygen Sensor
| Main Sign |
|
| How to Test | Diagnostic scanner, voltmeter |
| Do You Need a Mechanic? | It is recommended to hire one. |
| How to Fix It | Fix or repair the O2 sensor. |
Your car can also sputter when you’re driving because the oxygen sensors are not working. The sensor will check how much oxygen is being released in the exhaust pipe of your vehicle and then send this to the ECU.
If your O2 sensor sends the wrong information, there will be too much air in the combustion chamber, causing your car to sputter. To replace it, you should identify the location of the sensor and disconnect it. Then, you can remove it and install a new one. Replacing the sensor takes a short time and little know-how, but if you’re not confident, it’s better to hire a mechanic.
7. Worn Out or Faulty Spark Plugs
| Main Sign |
|
| How to Test | Remove the plug and check the color. The normal color is brown or grayish-tan on the side electrode. |
| Do You Need a Mechanic? | If you are not handy with tools |
| How to Fix It | Replace the plug. |
Another reason why your engine might misfire are if your plug and the wires in your car are worn out. Nowadays, you can use spark plugs for up to 100,000 miles before it requires replacement. If your car is older, you should get new plugs if the engine is sputtering.
You can easily change a plug. Once the engine is cold, disconnect the battery and the plug wires. Then, remove the plug and remove a new one. You will then reconnect the wires, connectors, and battery. It’s important to test your car afterward.
8. Worn Out Gaskets or Seals
| Main Sign |
|
| How to Test | Check the seals with a cold engine test. |
| Do You Need a Mechanic? | If you are not handy with tools |
| How to Fix It | Replace the seals and gaskets. |
The fuel system of your car consists of different seals and gaskets. You also have these in the exhaust system, cooling system, transmission, and engine. If any of the seals or gaskets become worn out or old, then it would affect the performance of the engine. This causes the car to sputter.
The best thing to do is to identify the seal or gasket that is worn out, remove it and install a new one. You can inspect the seals and gaskets when the engine is closed.
9. Intake Manifold Leak
| Main Sign |
|
| How to Test | EVAP smoke machine |
| Do You Need a Mechanic? | Yes |
| How to Fix It | Replace the manifold or the side that is leaking |
Leaking in the intake manifold can cause car sputters when you’re driving or your car is idle. It will cause an improper mixture of fuel and air in our car. This can also be because of a vacuum leak You can find this out with an EVAP smoke machine and test it when the engine is idling.
If you have a plastic exhaust manifold, you can replace the part of it that is leaking. You can also seal the leak with epoxy or weld the plastic together if it is not too wide. If the manifold is completely damaged, you will have to replace the entire thing or contact a mechanic for help.
10. Damaged Fuel Pump
| Main Sign |
|
| How to Test | Use a manual fuel pressure gauge and rev the engine. |
| Do You Need a Mechanic? | It is recommended to contact them. |
| How to Fix It | Replace the pump, and contact a mechanic. |
The final reason on our list that causes the engine to sputter while driving or idling is a damaged fuel pump. The pump can cause very lean fuel to go into the engine, as the fuel pressure will drop to very low levels. You can test it with a fuel filter and a pump. Use a manual fuel pressure gauge to measure while revving up the idling engine.
If the pressure is too low, you have to replace the pump. The simplest answer will be to replace the pump, although it is not advisable to do it yourself. Instead, you should contact a mechanic to replace it for you.
Conclusion
In this guide, we look at the answer to the question of what causes a car to sputter while driving, offering all the solutions you need.
Here’s a summary of what we covered:
- Your car running out of gas is the main reason why it might sputter while you’re driving, and you can fix it by simply refueling the tank.
- A faulty or clogged fuel system is another reason why your car will sputter while driving, and it can be the fuel lines or fuel injectors that need to be cleaned.
- A clogged or failing catalytic converter can make the car shudder, and it needs to be removed and cleaned with a pressure washer or replaced outrightly.
- A faulty MAF sensor can cause your car to sputter and will need to be cleaned or replaced.
- If the ECU is malfunctioning, it can cause your engine to sputter, and it’s best to hire a mechanic to repair or replace it.
If you’re unsure about what to do about your car sputtering while you’re driving or idling, it’s best to contact an auto repair service directly. But you can save money by trying to replace the worn-out parts or clean it out if it is clogged.
References
- https://afdc.energy.gov/vehicles/how-do-gasoline-cars-work
- https://www.uti.edu/blog/automotive/catalytic-converter
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