astro starting problem when wet

My 99 Astro has a starting problem that only happens when it is wet weather out. It cranks but will not start. The fuel pump runs but nothing happens. Sometimes it will start after a few tries, other times not until the weather clears. This is my wife's car and it's a real problem when she's at work on the Navajo reservation. Help!

Had the same exact problem, friend mechanic said to wait till it was dark and spray some water with a hose under the hood around the plug wires and distributor and then have somebody try and start it and watch under the hood, What a light show!! Seems GM's plug wires are pretty much worthless after 36K, changed the wires with some life time guarantee ones from NAPA and also did a new cap and rotor at the same time and I swear it runs better than when we brought it home new!!

Had same problem with an old chevy. the cap was bad had a small crack in it. every time it rained NO START. :)