Robby,
Doesn't seem to matter if the fuel tank level is low or high.
The P0171 code I think is a lean mixture on bank one ?
So if I have my head on straight this morning, for it to be a fuel delivery problem I would have two error codes, both P0171 (bank one) and P0174(bank two) In my mind this kind of rules out the mass air flow sensor and does point to an 02 sensor but which one? I supose I should bite the bullet and invest in a decent code reader.
Thanks,
Bill,