January 28, 2013, 1:10 pm
Mafs tend to clean themselves every so often. The mafs run a very high electrical current for a few seconds through the platinum sensor wire, so the wire gets red-hot (1000 deg C). This burns off much of the contaminants, and tends to help keep the MAFs working much longer between manual cleaning or replacment intervals. If they need cleaning you tend to find you get driveability issues such as low revs, poor fuel economy etc.
You can clean the sensor manually by using cotton buds and electrical cleaner just be careful you dont drop it as they're very delicate and be very gentle when your cleaning the wire (I'm sure they're in the region of £100 mark or something lol). You should notice the difference in the appearance of the wires as they clean up. As stated be very careful when you're cleaning the wires with the cotton buds etc and soak the cotton buds with the electrical cleaner. Also make sure the sensor has dried properly before replacing.
Please note this is obviously not an exact guide and any advice you take from it and apply is at your own risk