I ordered a MAF which did not work correctly. I spoke to them over the phone and they advised they could only exchange for a new one, they would not return the item. I then spoke to the Nissan dealership (2002 Xterra is the vehicle) who advised aftermarket MAF's never work. They ordered a factory MAF and it now works fine. I tried to return the aftermarket MAF for the core, which I was told was authorized and now they will not even do that. read full review »