The last three times my 2001 F-150 triton has started running rough, I brought it in to see what was going on and the computer said the number cylinder was not firing. My mechanic replaced the spark plug and off I went.

The next two times the number 6 and 7 cylinders were miss firing. This time he noticed they had water on them. It was right after a heavy rain. I drove to work in the heavy rain and the engine was fine, but when I left the engine was acting up agian.

My mechanic has been able to prolong visits by spraying silicone on the spark plugs. Does any one else have a better solution?

Thanks

wheel bearing greas around the coil and on insides will keep water out and prevent rust

Yeah, put some dielectric grease around the seals from the coil to keep water from getting into the plug hole.