Im having a problem with an intermitent misfire . It started about a week ago after a trip to the gas station to fill up and a car wash. I washed the engine down without the plastic covers on because of an oil leak. The car ran fine till the next day. It started to miss after it was warmed up, but only under load. It would idle ok. Its gotten progresively worse.In park it will idle, but it backfires through the exhaust when I goose it. I changed out the fuel filter today with no luck. Could be funky gas I guess, but havent figured out how to dump it. I read a post pertaining to plug wires, but hate to go that route till I get some feedback from you guys. Seems weird that the wires would be the problem. Im thinking that some connection under the hood got wet. Any suggestions would be most helpful. Thanks.

 

Well, you got water on some electical component that it didn't like. I've washed my engine many times, no problems.
Did you use the high pressure coin wash? I would not wash an engine using high pressure, it's going to get watter in everything.

 

I think the water was the main problem. Its gotten 99% better this past week. Still has a miss once in a while, and I still have a 1/4 tank of the suspect gas. After further inspection of the new fuel filter, I found a slight kink in the outlet side fuel line. Seems to be a bit tricky getting the lines to lay the way they are supposed to. I cut the old filter apart and it looked pretty nasty inside. May have been the original filter.The car came from Florida . I brought it to South Dakota last fall and have been using premium fuel with 10% ethenol. That might be a factor too.( the ethenol)

 

when you wash the engine it is a good idea to cover all exposed electrican connections, including the coilpacks,