Why won't my car start when it rains?

[Maroon 5.0 LX]

It's more than likely the plug wires. When they get old, the wires and insulators get porous and absorb moisture, causing a no-start problem. Also check for moisture in the distributor cap and dirt around the plug porcelain where the wires slip on.

Of course there are other things that could cause your problem, but start with the basics.

I had an '86 5.8 van, everytime it rained, or even very high humidity morning, it wouldn't start. Although the wires and cap were not too old, replacement cured the problem.