I had the check engine code P0174, too lean on bank 2, come up the other day. I cleared the code and cleaned the MAF since I read on the internet that the MAF can become dirty or oily especially with the installation of a CAI. I did install a CAI but several months ago.

Anyway, I will see if it returns. I think I need some adjustment on the tune due the new CAI (BBK).

Anybody had this before? Otherwise the car (2006 Mustang GT) runs fine and at the time it didn't seem to miss a beat at all.