Contour Enthusiasts Group Archives Forums General Troubleshooting zetec misfire problem when raining/damp out

98 zetec, newer plugs,wires, fuel pump. when its damp or raining out it misfires under load at all speeds, idles ok. rechecked plugs , wires, listened to injecters , did all tests known for ignition diagnosis. was running fine until i hit some rain tonite, then it was misfiring and detonating under acceloration and up hills. please ,help or give me an idea. like i said i did spark tests,shorting tests ,.....everything

Let your car dry out for the night.. What you can do is take some water and poor it in the engine and find the area of wires that are shorting out. Once you locate the area seal it up with Silicon... or.. whatever it's just an idea. It could also be water getting into the trunk and shorting out some wires there. Or it could be water leaking into the Cabin Air Filter shorting out the computer on the passenger side?

I had the EXACT same problem with my zetec engine. When it rained I couldnt accelerate without it missing. I say MAKE SURE you get Autolite or Motorcraft plugs in there. After I replaced my plugs to motorcraft ones, it ran 2x better.