Has this every happened to you? A little more than one year ago, one of our clients was driving home from work one night following a heavy rainstorm, and struck a huge puddle at about 30 mph. A wave of water came over his truck and hood. The engine light immediately arrived, and the engine started to misfire. That lasted until he got home. The next morning when he turned his car on, the engine light came on and the car misfired. After about 10 minutes of driving, the misfiring moved away. That routine continued for about three days. On the fourth day, the engine began normally and seemed fine. A few days later, the engine light went out.
Matters were subsequently fine for a couple of days, until it rained overnight. The morning after, the light came on again, and the engine started misfiring again. It occurs whenever it’s rained or when it’s really humid. His feeling is that when he hit the water with a hot engine, something cooled and cracked, exposing something electrical, and also the humidity is causing the issue. Sound familiar?
This seems like the most fundamental of water-related automotive problems. This automobile has an old fashioned distributor cap and rotor. Most likely, when you forded the Nile that night, you got water in the distributor cap, and it’s causing the misfire by creating a short circuit. And I would suspect that this type of problem is exacerbated by old spark plug wires that “flow” electricity when there’s moisture or a lot of humidity in the atmosphere.
This used to occur to cars all of the time. Distributors and older wires would get wet on rainy days, and automobiles would perish and strand people. AAA towing service still refers to this time as “The Golden Age”! But with distributorless ignition systems today, and fuel injection that prevents flood, cars that don’t start or run in the rain are really rare.
In your case, what’s happening is that the moisture that is stuck in the distributor cap is compromising your spark. The spark is adequate when all the other conditions are ideal, but once wet or rain air steal extra electricity via the old spark plug wires, the engine begins misfiring.
Eventually, as the engine warms up, the moisture in the supplier disappears, the plug wires warm up and dry out a bit, and also the cylinders all flame. But when the motor gets cold, the moisture re-condenses within the distributor cap, and about the next rainy morning, you have the same issue.
As you may have the ability to repair it simply by removing the distributor cap and drying it out really well, I would recommend replacing the cap, the rotor and the wires. That stuff’s cheap. And it should fix all of your moisture-related issues.