Hi again,

Having the engine cutout out on a rainy day is a good sign of real bad ignition wires. A nighttime test with a spray of water mist may show voltage leakage down the outsides of the wires or jumping over to metal.
Onkel is pretty sharp on suggestions. I believe it about the caps on the spark plug ends. I have learned to tighten them with pliers if by chance I have to use those type of wires that require them.
Bad wires or connections can cause delays in spark delivery so while thinking about knocking or timing the wires would not necessarily cause an early firing but power loss is definitely in the mix for sure.

A word of caution about the AMM. Do not plug or unplug it while the engine is runnning. As far as that goes never unplug anything electrical on a car while it's running.

Having the morning rain was a "blessing from nature," even though, it's the weather that breaks things down with age and corrosion that may be interpreted differently.

Phil