The mass air flow sensor (or MAF) detects the volume of air coming into the engine so that the computer can accurately calculate the air/fuel ratio for the optimum performance and efficiency. As a sensitive intrument, the MAF sensor can become dirty and deteriorate over time, affecting its readings. Malfunctions can cause reduced performance, poor fuel economy, and the ominous ‘check engine’ light. This MAF has been Manufactured by Continental-VDO in Germany.