Chevrolet Repair: Our 1994 GMC Jimmy wont start all the way, distributer cap, gmc jimmy

Question
My 1994 GMC Jimmy has been acting weird. It won't start when it is wet or moist outside. It won't start at night either. Lately it will start during the day, espically after the sun has been shining on it. Sadly however, it did not start today and the sun had been shining on it for a few hours. I turn the key in the ignition and it tries to crank but won't fully start all the way to where it runs. I have already replaced the Ignition Control Modulator, as it turned out to be bad, according to tests on the original Ignition Control Modulator at Auto Zone. I have no idea what the problem may be now. Could it be the fuel pump, fuel filter, moisture in the distributer cap, a battery going bad, a starter going bad? It could be a dozen things. It's very frustrating. It's a second auto my family and I use weekly. It, I hope is a simple problem. It's a 12 year old auto and I don't want to put much money into it. Can someone help me please. Thank you.

Answer
Hi Bladei.... when did you last tune this truck up.... if it starts ok when it is warm and dry i would suspect that you need a cap, rotor, wires and plugs...don't forget fuel and air filters...quick test is get it running and in the dark use spray bottle of water and spray the wires and cap...if you see sparks jumping off wires that means they are bad....hope this helps