Mod shortlist: 19T, 550cc, AFPR, Supra Pump, FlashECU/Chrome, Montero MAF

It idles fine, but rich, like 11-12 AFR after closed loop. 15 AFR in the first 10-20 seconds of running.

Accelerates normal at first when not boosting, then when boosting it breaks up bad. The more it's driven, the worse the problem seems to get, to the point where it breaks up with any kind of throttle, boost or not.

Pressure tested, found a few major leaks, and fixing them had absolutely no effect on the problem.

Checked the front 3 plugs, and they look good.

Fuel pressure is normal. AFPR is functioning normal, but there is a miniscule amount of fuel getting to the vacuum part of it. MAF readings appear normal based on experience.

While I had it idling for about 20 minutes, I watched the low fuel trims go from 2% to +10-12% and hold there. This was after fixing boost leaks.

Today I found all 4 O2 sensors are reading 0v or close to it, and have no reaction to revving the engine. They only react to unplugging them, which makes them go from .03v to .01v.

Is it possible I have 4 bad O2 sensors at once?? Or maybe I tuned with some failing O2's and didn't notice? Could these cause a fuel cut like misfire??

Would driving in open-loop test that theory?