2003 Cargo Van will not start in rain/damp/wet weather on 2003 Chevrolet Express 1500

2003 Express 1500 runs great EXCEPT when it damp or raining. Then it will crank (battery new), gas pump no problem (pumping pedal you can smell gas) but it will not start. As soon as the weather changes - within one day, it starts immediately.

Asked by for the 2003 Chevrolet Express 1500
I'm thinking ignition issues. Think Distributor cap, rotor, ignition wires. These are areas that moisture makes a huge difference. As soon as things dry out - everything is fine.