'89 Toyota PU, won't run when wet?

The ignitor is mounted on top of the coil. It is black and does not have a heat sink. I think I have one for a 91 22re pickup around here somewhere. Also there is a rubber boot that some cars/trucks came with that goes around the distributor.

The air flow meter box by the air filter could take on water if someone broke the seal around the plastic cover. rtv would be fine to fix that. Another thing is the tps on the throttle body might be causing problems, try unplugging it when you have issues and see if it runs.

Did you pop the coil wire out and check for spark? is that how you know it is ignition related?