I have a 1990 F150 with a 6 cylinder engine. It has about 70,000 miles and runs great…when it is not raining. It cranks over great but does nothing…being a part replacer and not a mechanic I replaced the distributer cap, spark plug wires, and rotor… no luck…but now that it has stopped raining in Albany California… it runs great… what should I replace now? This happened once before and maybe I wasn’t paying attention, but I think it ran fine after the wiring changes even in the rain.
There’s probably an ignition coil in that system somewhere too that you’ll want to take a look at.
You can find out - get a mister bottle with water in it, run the truck and start misting with water. Whatever disrupts the engine when you mist it is a pretty good culprit.
The most common cause of this condition is spark plug wires. Fords especially are prone to this condition.
Right but s/he said the wires are new.