A Bad Mass Airflow Sensor Could Cause Your Check Engine Warning

If your check engine has come on and it won’t turn off, it could be the mass airflow (MAF) sensor. This sensor lets the engine control unit (ECU) know how much air is flowing into the engine. If the MAF sensor malfunctions, it will send an error code to the ECU and the ECU will turn on the check engine light. J&S Auto Repair advises this is just one indication that your car has a bad MAF sensor. Here are other signs of a malfunctioning or dirty mass airflow sensor.

Acceleration Lag

The ECU takes the MAF’s data and makes adjustments in the combustion chamber. Sometimes, it puts too much air in the chamber because the MAF reading was off. This will cause your acceleration to lag.


The ECU can also put too much fuel in the chamber due to faulty MAF sensor readings and you will end up with black engine exhaust. The exhaust is caused by the engine burning away the extra fuel.

Engine Hesitation

Engine hesitation is much like acceleration lag. Your engine will hesitate and sputter if there is too much air in the combustion chamber. You might fear that your engine will stall. This could happen if the MAF sensor readings are really off.

Engine Surging

The opposite engine reaction happens when the air/fuel mixture is rich. Your engine will pick up speed or surge even though you aren’t pressing down harder on the accelerator. This, too, can be caused by faulty MAF sensor readings.

Difficult Starts

You may also find it difficult to get your car started. If the engine is fuel-starved because the MAF sensor is malfunctioning, it becomes harder and harder for it to generate combustion and fire up. It may take several cranks to get the engine going.

Bad Fuel Economy

Another symptom of a dirty mass airflow sensor is poor gas mileage. If you keep track of your mileage and notice that you aren’t getting the miles-to-the-gallon that you used to, it’s possible that your mass airflow sensor is to blame. 

Rough Idling

Finally, another sign of a fuel-starved engine is rough idling. When you are sitting at an idle, your vehicle shouldn’t shudder. If it does, you’ve got a problem in the engine that could be attributed to the MAF sensor.

J&S Auto Repair in Warwick, RI, would be happy to inspect your mass airflow sensor and resolve whatever problems it is causing. Give us a call today.

Photo by Marila Demchenko from Getty Images via Canva Pro