Hey guys, I just purchased a 2000 S4 and a few days later the engine light came on so i checked it with the obd tool and it came up P1113 which is the mass air flow sensor sending the code... Anyone think of any reasons it may have triggered? i dont have a aftermarket intake cause i heard that sets it off. And another question i heard it is bad for the S4 to install a blow off valve. I think it would be better because after i accelerate and hear the Turbo spool up and i let off the gas sounds like the turbos trying to relieve pressure..? ok to install BOV?