I recently picked up a 1997 Ram 1500 5.2 4x4, I am having issues with it firing when it is wet outside. I was leaning towards a cracked distributor cap and or a bad rotor, after doing some research last night I see the coils can cause this problem also. is there a way to test the coil for a crack?

 

Wait until its dark out. Get yourself a spray bottle, with just water in it. Open the hood, start the engine, spray a mist of water over the distributor, (gonna be fun to see....) plug wires, and coil. If you get a light show, replace the stuff that sparks when wet. If it has been a while since the last tune up, wouldn't hurt to just change them in any event. Runs bad when wet is generally a sign of old plug wires breaking down.

 

It runs great when it starts (wet or dry out), I am pretty sure it's been a while since it had a major tune up, so I agree it definitely will not hurt to change everything.
I am just looking at the root cause of the no start issue (yes coil way easier than cap & rotor) wires and plugs already planning to replace