[LMP]

Obviously as you mention, misfire is your problem, a common feat with this engine. YOu have a spark problem, period. There is no indication you have changed spark plug wires. And contamination in the coil shroud that goes to the spark plug that the coil is sitting on also occurs and shorts the spark to ground around the spark plug. Spark is always easy at low power; as soon as you increase throttle, the spark requires more voltage and this is where leaks takeover and spread the spark elsewhere. Do not spoil money all across the board: just spark plugs , coils and wires.