The problem with mafs is that when they get fouled, it is usually a mixture of dirt and oil. (Exhaust resideut, other oily componebts).


This mixture will eventually form a hard 'oxide like' coating that will not be dissolved with solvents.


Often times you can clean a maf and see some improvement, but if you do you should plan on replacing. Since youve only taken off the top layer.




Be VERY VERY careful about Asian/3rd world counterfeits. Even down to copying the Bosch box and packaging. In fact, Bosch has a website on how to spot counterfeit plugs, mafs, components. It is a big problem. No name ebay vendors AND the guys we see on these forums. everyone is getting burned.