Have had a P0306 and a P0316 error codes for a while now and have changed the spark plugs, coils, intake manifold gasket, checked injectors and changed the injector for the cylinder misfiring(6). All of the sudden today a new error code has popped up, P219B and connected my OBDII scanner and see that the oxygen sensor B1-S1 has a current that fluctuates from -.05to .04 while B2-S1 is constantly between -0.30 to -0.17 all at idle. The voltage for B1-S2 is constantly at .80v while for B2-S2 it fluctuates from .07 to .11. The LTFT B2 is 14.84% while for B1 its 3.12%. At 1.75 rpm STFT B1 goes down to around 0 but B2 does not go lower than 3%. Also, I literally just drove over some snow a couple of seconds ago and now the Service AdvanceTrac light is on and Traction Control Off light is on. Fuel System 1 reads closed loop but Fuel System 2 is reading open(—). Intake air temp is 107.6 while ambient is 37.4.
Aside from the the Traction Control warnings, your fuel trims, Fuel System readings, and P219B all point to lean misfire on the bank that includes cylinder #6. Despite your repairs, P0306 and P0316 will likely return.
Check the condition of cylinder #6. Perform a compression test on all cylinders with a compression gauge to check for a loss of psi greater than 15% on #6. A quick, less effective compression check would be to floor the gas pedal on a cold engine, open the driver side door and crank the engine for 15 seconds, listening for an audible imbalance in the sound of the starter.
Another method is to check the power of cylinder #6 at warm idle. Disconnect each spark plug boot -- or each fuel injector electrical connector -- one at a time. Note the drop in engine RPM with each cylinder. If #6 does not drop as much as the others, compression is bad (since you have already checked the spark, fuel injector, and air induction to cylinder #6).