Sensor Problems: Several sensors can cause this type of behavior:
* Mass Airflow Sensor (MAF): This sensor measures the amount of air entering the engine. A faulty MAF sensor can provide inaccurate readings, leading to a lean or rich fuel mixture, causing sputtering and misfires. The engine light is a common result.
* Throttle Position Sensor (TPS): This sensor tells the engine control unit (ECU) the throttle position. A faulty TPS can cause erratic fuel delivery, resulting in similar symptoms.
* Oxygen Sensor (O2 Sensor): This sensor measures the oxygen level in the exhaust. A malfunctioning O2 sensor can lead to incorrect fuel mixture adjustments, resulting in sputtering and a lit engine light.
* Crankshaft Position Sensor (CKP) or Cam Position Sensor (CMP): These sensors tell the ECU the engine's rotational position. A faulty sensor can lead to misfires and erratic running.
Spark Plug Problems:
* Worn or Fouled Spark Plugs: Worn spark plugs can't generate a strong enough spark to ignite the fuel-air mixture consistently, causing misfires, sputtering, and rough running. Fouled spark plugs (covered in carbon deposits or oil) have the same effect.
* Spark Plug Wires: Damaged or worn spark plug wires can prevent proper spark delivery to the plugs, resulting in misfires.
Other Potential Causes:
* Fuel Injector Problems: A clogged or faulty fuel injector can prevent proper fuel delivery to one or more cylinders.
* Ignition Coil Issues: A failing ignition coil can prevent a cylinder or multiple cylinders from firing correctly.
* Vacuum Leaks: Leaks in the vacuum system can disrupt the fuel-air mixture.
* Low Fuel Pressure: Problems with the fuel pump or fuel filter can reduce fuel pressure, leading to sputtering and rough running.
* Catalytic Converter Issues: A clogged catalytic converter can restrict exhaust flow, causing back pressure and affecting engine performance. This is less likely to cause immediate sputtering but could contribute to the overall problem.
What to do:
1. Get the Diagnostic Trouble Codes (DTCs): The engine light is triggered by stored DTCs. A local auto parts store can usually read these codes for free. The codes will provide valuable clues about the underlying problem.
2. Inspect Spark Plugs and Wires: Visually inspect the spark plugs and wires for visible damage or fouling. This is a relatively easy check you can perform yourself.
3. Professional Diagnosis: Based on the DTCs and visual inspection, you can decide if you want to attempt a repair yourself or take your vehicle to a qualified mechanic for a proper diagnosis and repair.
It's impossible to pinpoint the exact cause without more information (specifically the DTCs), but the symptoms strongly suggest a problem with either fuel delivery, spark delivery, or a sensor that controls those systems. Getting the codes is the crucial first step.
