I just finished 8 hour brake job due to (4) very stuck rotors and I am beat. MIL on and code reader indicates error code P 0170 - Fuel Trim Bank 1. Wondering if it is more likely that it is MAF than an O2 sensor (?) Unfortunately I didn't spring for the better scanner so I don't have O2 readings.

BTW - I have been guilty of filling up the tank with the motor running but I have reset the error code 3x since then. I doubt it is just the gas cap.

 

That was the code for my MAF....I think you have it figured out.