Newbie Here. Help?? Truck is 01' 1500 360 4x4 and when its nice out it runs great. If it rains or snows it won't start. New Battery 3 weeks ago and last week a new crank position sensor also a tuneup back in December. It's getting spark and fuel. What can it be. Truck has 115,000 miles.

 

i had a old car that did the same thing but it gave intermittent spark and it turned out to be the distributer cap

 

Easily 95% of the time ... a starting problem when humidity is high can be traced to the secondary ignition system (coil, cap, wires, plugs). What was included in your tune-up? If the cap was replaced, I would suspect coil or coil wire (to the cap). Next time it won't start ... spray the coil and the fat wire coming out of it with WD-40. See if that fixes anything.