Originally Posted by dyn085
As for the PCM/ECU, that I can actually vouch for. I hand calc my fuel mileage out of old hyper-miling habit, and every time I've had my vehicle reset (mft, 12B37, mft, mft again) my mileage immediately drops back down to 26. The total mileage on the car has always been irrelevent to the mileage- my last reset was at about 3k miles.
It's so strange that different drivers get such different results with this car. I don't have MFT but after 12B37 I've noticed no substantial change in mileage, car- or hand-calculated. Just a definite worsening of shift quality.