if the bank is to lean, will this cause misfires?
Yes, an extreme lean state can cause a misfire or two, most likely though the engine is not getting enough air or it could also be exhaust backing up into the cylinder, but please tell us more about your problem.
Lean is too much air, not enough fuel. In reality its the otherway around. Misfires can cause lean condition, if your not getting enough fuel or fuel at all on a cylinder. It is possible that the o2 sensor is reading so wrong making the motor run crappy.
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