John, I would give the ignition system a real careful check. Wet weather related skipping and misfire symptoms can be an indicator of a High voltage leak causing a weak or intermittent spark. If the coil tower (where the high voltage cable goes) is dirty, or has a small crack, the high voltage (HV) can find a sneak path to ground. The same holds true with the inside and outside of the distributor cap. If you have a HV leak, meaning it arcs to ground, you can sometimes hear it as a snapping noise. The wires themselves can loose their insulating value and leak HV. Looking at the motor while running in total darkness can sometimes allow you to see the arcing. If the wires are grungy, this can cause arcing especially where they plug in around to the cap or coil. When arcing persists, an arc track can burn into the coil or distributor cap. If the wires, rotor, and cap are old, this would be a fine time to replace them including plugs if they are in need. The coil tower should be cleaned with WD-40, and given a real careful look for a tiny crack or carbon track. If this does not fix it, you have eliminated a common cause, and can move on. I hope this helps.
Guy K.
