When your car engine sputters, it’s clear that something isn’t working right.
You’ll feel intermittent power and the relative change in noise. The car will most likely feel like it’s lurching or otherwise struggling.
Before continuing to read through this guide I made for you, check you have enough fuel. You could have an issue with the fuel gauge.
If that all seems fine – perhaps you filled up only a few days ago? – there’s something deeper at play.
So, what can be done about that? How can you best fix a sputtering car, and why is it important?
Let’s get started! I’ll start with the main causes.
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What Causes A Car Engine To Sputter?
A sputter could have its root cause in a number of things.
In short, the power isn’t being generated by the engine smoothly. The problem could also lie in your transmission, which is, of course, connected.
Your internal combustion engine mixes air (oxygen) and fuel (gasoline or diesel). The spark plug ignites this, creating an explosion that drives a piston down.
Through connecting rods (con rods), this reciprocal motion is converted into rotational force. It then passes through the transmission for gearing and finally turns the wheels.
Sputtering could be caused by anything irregular in this system. However, the most common problems will be fuel, air, or sensor related.
Here are a few of the most usual. Problems with the…
- Fuel pump
- Fuel filter
- Fuel injector
- Spark plug
- Throttle body – dirt can prevent airflow at idle
- Mass Air Flow (MAF) sensor
- Vacuum leak
- Catalytic converter blockage or oxygen sensor failure
- EGR valve clogged
If the problem lies with one of these (and it most likely does), you’d expect the component to be only partially damaged, dirty, clogged, etc.
Some of the time, it works fine. The rest of the time, it doesn’t. That’s what leads to this intermittent low power, or “sputtering.”
This article examines your problem by symptom. However, any of the signs listed below could be caused by any of the above.
A qualified and trusted car mechanic should perform all diagnosis and repair work.
Car Engine Sputters While Driving Along And Idling
If your car’s engine won’t stop sputtering, the issue probably lies with the fuel system or MAF sensor.
The sputtering feeling is a sudden change in power produced by the engine. It feels like it’s lurching because it’s generating a lot of energy and then not much. This cycle repeats.
That’s why the fuel system is the most likely culprit. The air intake system doesn’t have much space for this intense variation.
That being said, it never hurts to check out the following:
- Throttle body and plate
- MAF sensor (more on that below)
The fuel system, though, has plenty of areas where the gas flow might be intermittent. It passes through the following:
Blockages or pressure losses in these areas impede the liquid/vapors. As a result, some cylinders might get too much fuel while others get none at all.
This is, in essence, a type of misfire. Have a mechanic check the entire system thoroughly.
The MAF sensor is responsible for telling the ECU how much air (“load”) is coming in. The computer then sends a corresponding amount of fuel to the injectors.
If the MAF reading is too high or low, the ECU will send too much or not enough gasoline to the cylinder. This creates a rich or lean mixture (more or less power than needed). If the readings fluctuate constantly, you’ll get that lurching, sputtering feeling.
In rarer cases, the issue could lie with the control module itself. You could have an automotive electrical engineer check out the ECM (Engine Control Module).
Car Idles Fine But Sputters When Accelerating
If your car’s tick-over is regular, but the sputtering starts when you put your foot down, you should check the throttle position sensor (TPS).
The TPS might be clogged or damaged. Since you don’t touch the pedal when your car’s idling, it will have no impact at this stage.
Once you accelerate, though, the readings are sent to the ECU from the TPS. This then calculates how much fuel to pump into the chamber.
Strange TPS readings might lead to intermittent amounts of gasoline entering the engine.
Have your transmission fluid and the TCM (Transmission Control Module) inspected if the TPS seems fine.
Like the TPS, the transmission has little to do with when your car is idling. Once you begin moving, it kicks into life.
Problems with the transmission might manifest themselves as a sputtering feeling.
After this, you should have a more in-depth check done on the fuel system and for any misfires (spark plugs, ignition coils, etc.). In most cases, you’ll find this affects your vehicle at idle, too. Still, specific issues might only become apparent when accelerating.
Car Sputters When Starting And Idling
If your car sputters while you’re stopped, the engine is struggling to maintain its idle speed. This is known as tick-over. It’s verging on stalling at idle.
The most likely cause here is an issue with the idle air control actuator, fuel system, or a general misfire. The MAF sensor could also be dirty or damaged, or the EGR valve could be badly clogged.
A quick clean of your throttle body might fix the problem. Otherwise, a mechanic will need to take a closer look at your engine.
They’ll then identify the problem and give you a quote. If you’ve eliminated the throttle body problem, you’ll probably be paying for work on the following:
- Spark plugs
- Ignition coils
- EGR valve cleaning
- Fuel filter or pump
- MAF sensor
Car Sputters When Starting
If your car sputters when starting but then runs normally, there is most likely an issue with the starting system.
When you turn the key, the battery connects to the starter motor. This spins the flywheel on the crankshaft and means the engine can start running under its own power.
Most normal misfires will manifest themselves during starting and running. The only differences during the starting procedure are:
- The engaged starter motor (powered by the 12-Volt car battery)
- A rich fuel mixture to help with starting
The problem is probably battery related. If it isn’t, check out the starter motor and the rest of the starting system. Finally, look for generic misfire symptoms that might be minor enough to be masked when the engine is running.
Conclusion: What To Do About A Sputtering Car
The main point to take away? If your car’s sputtering, it’s struggling. Go straight to a mechanic.
These things don’t fix themselves. The quicker you take action, the faster your car will be repaired and the less it’ll cost!
A sputtering engine will likely cost a few hundred dollars, including labor and diagnosis. The final total will, of course, depend on what work needs doing.
Leaving it without inspection or repair could lead to severe engine damage. Don’t take the risk.