i have a 1994 ford f150 xl and for the past 9 months everytime it has rained or fog my truck will not run. it will run in the rain and even after it rains but a few hours later it starts then dies instantly. on the second day it will usualy start and run for about 10 seconds then bog down, sputter, drop power, slowly die whatever you wanna call it then it just shuts off i gotta wait a few soconds to try and crank it again because it wont crank at all if i dont. i noticed if i can get it to run for about 10 seconds i can rev the engine up to about 3000 rpm and heat it up and it will die again but after about 15 minutes of cranking it and reving it i can get it to stay running for about 2 minutes and then the check engine light comes on and it runs fine the check engine light comes on for about 2 minutes then shuts off and when i drive the truck after i do all this it will shift really hard. changed fuel filter, fuel line, spark plugs, plug wires still does it some of these will fix it for a day or 2 then it just stalled again i have 2 gas tanks 1 of them doesnt work i dont know if that has anything to do with it. thanks for taking the time to read any help is apreciated

 

Sounds like plug wires... You said you replaced them.. What about the cap and rotor?

 

My son has a 1994 which started having the same issue. Every time it rains it continues to start running rough to the point of dying and not wanting to start. Mass air flow sensor, distributor cap, rotor, plugs, plug wires, throttle position sensor, idle air control sensor, coil replaced but issue continued. Seen a post where a guy mentioned the intake air temperature sensor. Found it to be extremely dirty so I cleaned it with mass air flow sensor cleaner. Instantly started and has not caused any more issues when it rains. Hopes this helps those fighting the same thing.