Verify injector pulses like mentioned as well as fuel pressure, clean air filter, compression test those cylinders and compare them to good cylinders on the opposite bank. I always cover the basics first saves you lots of trouble down the road. If all that checks ok...
Mark the top of the coils with a marker indicating what cylinder they're on now. Then try swapping the coils from both cylinders that are missing to two known good cylinders, this will let you know if the coils are bad if the miss moves to those cylinders.
If that does not fix the problem, I used to see a lot of them things have the egr valve stick open and cause cylinder misfires on the the back bank as it draws the egr gasses first due to the valves placement on the intake. Sometimes they will throw a egr flow code for this but most I've came across do not. I've even seen the intake explode on those years, when the egr valve sticks open it pumps raw fuel back in the intake on cold morning start up.
