Also known as the MAF Sensor allows the vehicle to detect the mass of airflow entering the engine necessary for proper fuel mixture. Overtime the factory MAF sensor can fail or accumulate dirt and oil causing the vehicle into some running issues or light up a CEL (Check Engine Light). If your vehicle is running rough, hesitating after starting or experiencing poor fuel economy then you may have a problem with your mass air sensor. The MAF Sensor can easily be located beside the air intake box inside the engine bay.