Mass Airflow Sensor (MAF Sensor)

What it does

The MAF sensor sits in the air intake tube between the air filter and the throttle body. It measures how much air is flowing into the engine by using a tiny heated wire — air flowing past the wire cools it, and the sensor calculates airflow from how much electricity it takes to keep the wire hot. The engine computer uses this number to calculate exactly how much fuel to inject. A dirty MAF (contaminated with oil vapor or dust) sends wrong readings, and the fuel mixture goes off — causing hesitation, rough idle, and poor fuel economy.