The mass air flow sensor in the Pontiac GM engine is placed between the air box duct and the throttle body of the engine. Depending on the type of Pontiac you have, there are a couple of different procedures to remove and replace it. Mass air flow sensors can build up air particulates, which contaminate the sensor screen and cause poor performance of the engine. If you're replacing one, you already know they're expensive and you should go a step further and clean out the air intake system and change the air filter as well.
Locate the air box in the engine compartment of the Pontiac. Remove the cover and then remove the filter. On 3.1-liter and 3.4-liter motors--in the Aztec and Montana--it might be easier to disconnect the air duct using a screwdriver to loosen the band clamps and then remove the air duct before taking the air box cover off.
Use a shop vac to clean out the bottom of the air box if there is debris or accumulated dust present. You can also spray some throttle body cleaner into the air box bottom and wipe it out with a shop rag.
Locate the mass air flow sensor in the air duct tube. On the Aztec and Montana engines, the mass air flow sensor is cylindrical and made of aluminum housing. On the Bonneville and Grand Prix models, it is plastic and inserts into the air duct tube.
Loosen the band clamps on both sides of the air duct tube on the cylindrical MAF sensors. On the flat plastic MAF sensor, remove the four security Torx tip screws using a T-20 security tip driver.
Disconnect the plug leading from the MAF sensor to the wire harness. Remove the sensor.
Install the new sensor by reversing the procedure. Inspect the air duct tube for dust and dirt leading to and from the MAF sensor. Clean the duct out using the throttle body cleaner.
Install a new air filter into the air box when it is time to reassemble the unit.
