The Air Flow Meter (or Mass Air Flow Meter) is an electronic sensor unit which measures the air volume in the fuel mixture to the injectors, and corrects the calibration accordingly via the ECU. The less air being passed through results in more fuel, and visa verse. Both scenario cause different issues Therefore, if the Mass Air Flow Meter in your vehicle is faulty, it will inevitably lead to additional problems caused by too rich or too lean a fuel ratio.