My Ram runs like a champ until the humidity gets high and I leave it for more than 8 or so hours. It will turn over and try to crank but it just won't fire. It spits and sputters occasionally and blows white smoke. It also has a sort of "catch" in it while turning over. Sounds like metal on metal like the timing is off or something. If I put a heater under the hood for an hour or so it usually pops off no problem and runs fine afterwards. Any ideas???

 

The humidity might be getting to the coils for the spark plugs. Had a 2000 ford taurus that when started would skip because the water was grounding out the voltage required to make a spark. It would also happen on humid days. Change you oil and open the filter. Can usually tell a lot of what is going on. ie metal bits in filter.

 

Also check where the wires go onto the dist. cap and make sure they are not corroded.

 

How old are your wires, humidity can cause the wires to bleed.

 

Ford is known for cracked coil packs which cause issu'es in moist weather.(I'm well aware you have a dodge) Not sure what you have on your '02 5.9L??, but I would look into that aspect. A crack may or may not even be visible to the naked eye.
i wouldn't think it's your plug wires unless they ALL went at once(doubtful) or maybe the main coil wire is bad?