1992 ranger xlt spluttering and missing

Hi everybody. I have a 92 ranger xlt 4.0 V6, I’ve been having on and off issue these last few weeks with the truck throwing period spluttering fits when it rains heavy and gets wet. We’ve changed the plug wires on it but that seems to only fix it briefly. My next thought was to replace the coil pack but I wanted to get on here and see if anybody else with more knowledge than me could weigh in. Thank you

Rain is a big hint-- My money is on moisture inside the distributor cap--replace or dry out the old one. I've seen no starts- then put a hair dryer to the distributor cap for 5 minutes and it starts right up- without even removing the cap!