Motorcraft # AFLS131. - 2003-2009 Ford Explorer 4.0L & 4.6L engines w/ OEM # #3L3Z 12B579-BA only. NEW MASS AIR FLOW SENSOR, easy to install. TypeMass Airflow Sensor (MAF Sensor). Ford OEM Ref. # 3L3Z12B579BA, 3L8Z12B579BA, 3L3A12B579BA, XL3F12B579BA.