Actually you're wrong. They do get resistance over time, as well as carbon buildup. The MAF's actually overheat once in a while in an attempt to clean themselves, but after time, it'll in fact just lose it efficiency and have a slower reaction time just like 02 sensors. As I said, cleaning the MAF would be like cleaning spark plugs, 02 sensors or anything else that has direct contact w/ air, fuel, contaminants in the air, etc.

Cleaning vs replacing the MAF has been discussed for years on the E34/E39 540, E38 740 and E39 M5 boards long before an X5 even rolled off the assembly line. M5 board members, who have to deal w/ two MAF's, actually learned about the compatible VW MAF after one of the members did his own testing via the fuel readings on the OBC and bench testing using an ohm meter. At the end of the day, cleaning them was putting off the inevitable and we found a cheaper, compatible replacement. Sure, you can clean them and it MAY temporarily fix some problems...but it won't be back to operating 100 percent like a new one would, and it'll go bad again soon enough. People just panic and want to cheap out I guess.

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