My van is a 2002 and for the last 2 years it will give me trouble after sitting for a day on a foggy day. spring and fall never in the summer. completely inconsistent. Heavy rains do not seem to be a problem. Saturday night it was quite foggy would not start- tried the lighter fluid. The car will cough, almost turning over. attached it up to another car battery to keep trying to start it. left the car for 2 days, now it is crisp and cool out and the car started on the first try. My mechanic has sprayed the wires with drying stuff and that seemed to help for a bit. hard to tell. very annoying. says he cant see the trouble unless he can duplicate it.I can’t time it that way.
Foggy days see more humidity floating around. This smells of ignition problems, especially if a spray-on water dryer helped the problem. I’d start looking for places the high-energy spark can get lost between the coils and plugs. This is most likely where the problem is. If it is ignition wires and coil paks, I’d replace the wires. If it is coil-over-plug, look for cracked coil housings.