I have an 01 R/T Durango and have this problem. If I park on the dirt part of my driveway and it rains she won't start, or starts very hard, lots of cranking before it goes. I did replace all wires, plugs and dist cap and still have the same problem. I also discovered if I raise the hood a bit after the rain stops starting is better. I mostly park on the pavement in the driveway, but that's not always possible as I have 3 cars and only 2 can fit on pavement. Looking for ideas.

Thanks

 

Check your sparkplug wires for condensation on them and make sure they aren't touching eachother.
This tsb might help http://autorepair.about.com/cs/faqs/l/bl654h.htm