You too huh? :D
I didn't even bother trying to mention the firing order part of it (as in half the cap missing for example, does not mean you loose cylinders 2345, but 1843 or whatever) :D
Not all even numbered cylinders, or even all on one side could be anything but a loose rocker shaft, or malfunctioning ECU.
There is nothing else mechanical or electrical either one that can cause it to only run on one bank, well besides a plugged exhaust on a dual setup with no crossover.
I'm tellin ya, look for that potato. :D