The engine misfires in rain or just when is very humid. Runs great when dry. Changed the plug wires, roter and dist cap and still have same problem.
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2002 Mercury Villager Question: Engine misfires when weather is humid.
Answer #1DaveJHM November 07, 2010, 16:47Master
Make sure the wires you purchased are high quality or even better yet - original equipment wires. I still think you may be experiencing some arcing from the wires. The key thought here is the moisture content in the air when the problem occurs.
To confirm, get a spray bottle with water and while the engine runs, spray around the plug wires. See if the car stumbles.
Beyond that, you could have an injector or harness issue.