This car is still set up with the single wire, narrow band O2 sensor, as far as I know, the wide band ones didnt kick in until the later 80s 300zx ECU setups.
My sensor is an NTK specified for use with 79-83 280zx cars, which is the motor and ECU i have. The air/fuel ratio gauge is an equus 8366
Im gathering parts to do the 300zx z31 computer, MAF and crank angle sensor. The car is not actually running lean (as far as I can tell) and it survived that long roadtrip fine so I'l probably just wait till I do this swap to try again getting an accurate air/fuel ratio gauge working right.