The mass air flow sensor in your car or light truck measures the volume and, in some cases, the temperature of the air flowing into the engine's intake manifold. With this information, the on-board computer can calculate engine load, fuel trim and ignition timing. When the MAF gets dirty or otherwise contaminated, the sensor may lose accuracy and driveability problems will occur. Most MAF sensors can be cleaned to restore accuracy and proper function, if the problem is caught before the sensor is permanently damaged.
Disconnect the negative battery cable, using a wrench. Allow the engine to cool completely to avoid damage to the sensor caused by thermal shock. Thermal shock is a condition that causes damage to an engine part when a hot component is suddenly cooled. Electronic engine sensors are susceptible to this kind of damage.
Unplug the electrical connector from the MAF sensor. The MAF sensor in your car is located in the air intake between the throttle body and the air filter housing. Many MAF sensors are located in the air filter housing itself.
Loosen the clamps on the air ducts that connects the MAF sensor housing to the ducts. Remove the MAF sensor and housing from the ducts and air filter housing. Remove the two screws that attach the MAF sensor to the MAF sensor housing, using a torx driver. The most common sizes of torx screw used for this application are T 15 and T20.
Lift the sensor carefully out of the MAF housing. Remove the small O-ring between the sensor and the housing. Take care not to lose the O-ring.
Spray the electrical components on the end of the sensor with a liberal amount of MAF sensor cleaner and let the cleaner set for approximately two minutes to soften deposits on the sensor. Spray the softened deposits away from the sensor using the cleaner and allow the sensor to dry. In extreme cases, you can wipe stubborn deposits away with a cotton swab, but be careful not to damage the delicate sensor wire on the end of the sensor.
Slip the O-ring back into place on the sensor housing and slide the sensor into place on the housing. Reinstall the screws and tighten them securely. Reinstall the sensor housing into the ducts and tighten the clamps securely.
Plug the electrical connector back into the sensor. Reconnect the battery cable and test drive the car to allow the computer to recalculate the fuel trim and ignition curve.
Wear safety glasses and work gloves to avoid eye and skin injury caused by the MAF cleaner spray. Never spray the MAF sensor with carb spray. Carb spray will dissolve the protective coating used on the sensor. Use only MAF sensor cleaner.