Have you checked or replaced the plug cap on the faulty cylinder?
I`m not sure on the MC11, usually the cap is a resistor type.
Can`t remember but, I think the resistor in the cap is around 5k-ohms? It usually tells you on the side of the cap. Stick a multi-meter across it. Obviously, if it`s open circuit, it needs replacing. The reading wants to be somewhere near 5K, depending on the temperature.
Give the plug a good clean or replace it also.