GM Original Equipment™ Mass Air Flow Sensor (23256991) by ACDelco®. How your engine breathes determines how well it runs. And there’s no better way to keep your engine breathing right – and running great – than ACDelco. ACDelco GM Original Equipment™ Mass Airflow (MAF) Sensors are a high-quality replacement for GM Original Equipment, and are designed to give your engine’s control module the air-flow information it needs to burn clean and run like new. You – and your car – can breathe easier with ACDelco.