P2A00 - A/F Sensor Circuit Range/Performance (bank 1 sensor 1)

Jordo!

I think both those values are within range.

You want to log MAS A/F -B1 (V), MAS A/F -B2 (V), A/F WB-B1 (V), A/F WB-B2 (V), A/F ADJ-B1, and A/F ADJ-B2. I'd also log INJ PULSE-B1 (ms) and INJ PULSE-B2 (ms).

It's also worth logging MAF voltage for both banks just to confirm you don't have something wonky going on that far upstream.

Unless you have a specific physical symptom where you can narrow down when the problem crops up (e.g., stumbling at idle), once up to normal operating water and oil temps, I would try datalogging at idle, low load/cruise, and maybe one pull to redline in 2nd gear.

Unless the way things are plumbed for the turbo are causing Bank 1 to just suck more air than Bank 2 (it's possible -- and if so, then you'd need to apply fuel correction to Bank 1 cylinders via uprev tune), it could be a bad sensor, a vac leak, sticking injectors, or a fouled or cracked spark plug -- in other words, un-metered air slipping in, failing injectors, or a bad plug can all result in a lean condition, or at least cause the ECU to think you're running lean.

The code you got points to bad O2, but really it just means that the bank stays leaner than targeted longer than it should, so any of the aforementioned could cause that.

The datalog (as well as inspecting for vac leaks and checking out the spark plugs) should help clarify -- good luck!

EDIT: Also, yes, it's a bit like the random misfire code -- you can get this code and not have any actual issues, meaning its a detection logic problem, possibly aggravated by changing things around for the turbo. If everything looks good, all values are in range, no loss of power or evidence of knock, then I agree -- just switch it off. Definitely confirm all is good first, tho'.

__________________
Enjoy it. Destroy it.