First off, thoroughly check all connections leading to the coils. If OK, then swap the offending plug to another cylinder. No joy? See if you are getting power to the offending coil. If so, try swapping the coil and H.T. lead to another cylinder and see if the fault transfers. If no power to the coil, try wiring that coil direct to a known power source. If that solves your problem, then a check of the wiring to that coil will eventually reveal where your problem is. A wiring diagram is of benefit if the wiring is as it came from the factory.
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