GM Genuine Parts Mass Air Flow (MAF) Sensors are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These sensors are key parts of the engine management system, and are GM-recommended replacements for your vehicle's original components. The MAF sensor measures the amount of air entering the engine so that the engine control module can determine the amount of fuel to inject. This helps ensure the most efficient air/fuel mixture for the best fuel economy and power. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).