01 Tahoe, p0300 and p0174

Hey all. As the title states, I have a 2001 Chevy Tahoe that has been throwing p0300 (random misfire) and p0174 (bank 2 lean) codes. The engine is a supercharged 6.0 LQ9 which has been running great until recently. About 1/2 to wot it falls on it's face and you can hear/feel the misfiring pretty badly, and it hesitates for a second or two when given light throttle from a dead stop. Bank 2 is the only side that seems to run lean while bank 1 is running a little richer than normal. Before the problem, bank 1 would show an afr of about 13-14 at part throttle acceleration under load. Now since the codes, it's been showing close to 11.3-11.5 under the same load while bank two runs extremely lean. I've checked injector and coil operation, replaced both o2 sensors, checked for clogged cats, couldn't find any vacuum leaks anywhere, replaced intake gasket, installed new plugs and new fuel filter. Anyone have anymore suggestions or ideas? I'm going to swap the MAF later today and check fuel pressure also. Other than that, I'm about out of ideas.

Sounds like either a fuel pressure issue to that bank or an 02 sensor on that bank maybe? Any scan data?

O2 sensors are new on both banks. Data shows a lean condition on bank 2 only while under boost and gets worse as the rpms climb, especially over 3k rpm. I haven't put the motor in boost since I discovered the lean condition (boost + lean condition = no more motor). I'm thinking the lean condition and DTC may be due to a bad misfire on that bank, but imo, I need to isolate the misfire problem first to see if that's what's causing the p0174 code. Isolating the cause of this p0300 is what's causing me the headache right now.

Misfires as a rule don't normally cause lean codes. Or rich codes for that matter. Alot of the Vortecs have issues with injector nozzles leaking fuel pressure off and the fuel pressure regulator leaking as well causing codes. As well of course vaccum leaks from the intake gaskets on that engine and coolant leaks.

The injectors are 42lb Bosch injectors. Fuel pressure is good and injector coil impedances are within spec. Bypassed the EGR. Swapped MAF with a known good unit from my brother's truck. I just built the engine about 3K miles ago. 6.0 LQ9, 10.1:1cr, Lingenfelter cam, running ~8 lbs boost, NGK TR6 plugs gapped @ .035, dual fuel pumps. No coolant or oil leaks, no exhaust smoke, no foul plugs, etc. I'm going to swap the MAP sensor tomorrow and check for exhaust leaks in front of the bank 2 HO2S to see if that's causing the lean reading on that bank.

Did you changed the PCM or you are using the stock unit?

Look at the data and see if the pcm is increasing the injector pulse width on that bank and if both banks are equal. If all the inputs are good, map, maf, o2, tps, etc. The pcm may not be adjusting the fuel correctly.

The pcm is the physical stock unit but custom tuned for the engine/sc setup via EFI Live software by my tuner.
Everything including the injector duty cycles, pulse width, etc seem fine. I've also double checked pcm ground connections, chassis to engine grounds, etc.
BTW, thanks for the input everyone.