Which bank is going lean

[makriluc]

Hi guys.
Trying to track a little problem.
According to this, which bank is going lean?
1 or 2?
Thanks

 

[racecougar]

It appears that bank 2 is going rich as you step up the rpm, while bank 1 holds at stoich, but it would be helpful to scale the y-axis to the STFT's rather than battery volts.