Several potential causes could lead to both the surge and the illuminated engine light:
* Faulty Mass Airflow Sensor (MAF): This sensor measures the amount of air entering the engine. A malfunctioning MAF can cause an incorrect air/fuel mixture, leading to surging and triggering the engine light.
* Dirty or Faulty Throttle Position Sensor (TPS): The TPS tells the computer the throttle's position. If it's dirty or malfunctioning, the engine may receive inconsistent signals, resulting in surging and an illuminated check engine light.
* Problems with the fuel system: This could include a clogged fuel filter, a malfunctioning fuel pump, low fuel pressure, or issues with fuel injectors. Any of these can cause inconsistent fuel delivery, leading to surging.
* Vacuum leaks: A leak in the intake manifold or vacuum lines can disrupt the air/fuel mixture, causing rough running and surging.
* Ignition system problems: Faulty spark plugs, ignition coils, or wires can cause misfires, resulting in uneven power delivery and surging.
* Transmission issues (Automatic Transmission): Problems within the automatic transmission, such as a slipping clutch or a solenoid problem, can manifest as surging. In this case, the engine light might be illuminating as a secondary effect due to the transmission's interaction with the engine's control system.
* Faulty oxygen sensor: This sensor monitors exhaust gases to help regulate the air/fuel mixture. A malfunctioning oxygen sensor can lead to a rich or lean condition, potentially causing surging.
* Throttle body issues: A dirty or sticking throttle body can restrict airflow, causing surging and setting off the engine light.
To determine the exact cause:
You'll need to have the car's diagnostic trouble codes (DTCs) read using an OBD-II scanner. This will give you a specific code indicating the problem area. Auto parts stores often offer free code reading services. Then, you (or a mechanic) can investigate the specific component indicated by the code.
Ignoring the engine light and continuing to drive with a surging engine could cause further damage. It's best to get the problem diagnosed and fixed as soon as possible.
