New problem with this 2012 Yukon XL 1500 Denali 6.2L. I really hate this truck! GREMLIN is back

[testdepth]

I found a GMC TSB that describes what my truck is doing but it is for a 5.3 engine and 6L80E trans. Mine is a 6.2 engine and 6L80E trans. TSB APR 2013 PI0952

Vehicle owners may report a flare—an engine rpm increase during the shift—when the transmission shifts from 2nd to 3rd gear in cold weather. This typically occurs when the transmission fluid is cold.

• The condition is usually present only during the first few 2-3 shifts after the vehicle has been sitting for several hours.

• The flare goes away as the transmission fluid warms up.

 

[testdepth]

Truck has 171000 miles and is 13yrs old and I've been having problems with it that are random. Drive for 10 days with no problem and then problems start with surging while driving at speed under 50 or it stalls out like a few days ago. Then last week it drove fine all week. Then the recent stall and surging started. In the last month I've changed:
Iridium plugs, coils, throttle body, crank sensor, coolant sensor, fuel injection sensor, negative battery cables, valve cover gaskets, motor mounts, MAF sensor, Fuel pump w/ fuel pressure sensor tested fuel pressure at 43psi. I even tested the transmission pressures in this 6L80E and they were normal with dirty fluid. I went out there while it was idling and pulled on wires all over the engine bay trying to get it to surge or stumble but nothing happened. I also installed an AFM disable but these recent problems happened with it installed. It's a real PIA!

I tested fuel pressure and fuel trim at idle and at 2000rpm: These all look normal?
FUEL TRIMS:

IDLE
STFT BK 1 0 to 6
STFT BK 2 0 to 6
LTFT BK 1 1
LTFT BK 2 1

2000 RPM
STFT BK 1 -3 to 2
STFT BK 2 -3 to 2
LTFT BK 1 0
LTFT BK 2 1

Fuel pressure shown on scan tool is 43psi whether at idle or 2000rpm.

O2 SENSOR BK 1 SENSOR 1 constantly jumping from 70 to 800
O2 SENSOR BK 2 SENSOR 1 constantly jumping from 100 to 815

 

[prestige30165]

By chance has anyone installed a cold air intake on it? My 2012 1500 will not run properly with one installed.

 

[testdepth]

By chance has anyone installed a cold air intake on it? My 2012 1500 will not run properly with one installed.

No Sir it's all stock 6.2L with a 6spd 6L80E