Where is the best place(cheapest place) to get a Mass Air Flow Sensor from for an E46M3? Napa? Bmw? ????

Is there a way to check if the one in the car is bad?

Thanks

check out www.pelicanparts.com ...I like the site, they have alot of brand name BMW parts.

I don't know what your specific issue is, but sometimes a "bad" one can be fixed by cleaning with CNC MAF Cleaner. Takes 5 minutes.

A "service engine soon" light is a good indication it might just be dirty, however they do go bad. A new one is about $250 iirc.

Why do you think it's bad?

How would I test if it is bad? When I unplug it the car notices and runs slightly rougher. I have cleaned it with the MAF Cleaner