stacy

I have oil on one of my spark plugs causing a misfire. The car is running really rough when it idles, but when I get it over 2,000 RPM's it runs ok. could it be a bad valve stem seal, valve seals? I am stressed that its worse like the piston rings. Please help!!!!

ford fan

I would think that the piston oil control rings would have similar wear on all cylinders. I guess it might be but doubtful, I would look towards the cylinder head. About a month ago a friend of mine had a the same thing going on in his 97 mustang. The ford dealer said that the number 7 cylinder had "super low compression" and that the car needed either some head work or a new long block, @$2250/$3500. This sounds crazy but a trip to autozone for a new 4pack/coil $40 the damn thing is not fowling the plug it idles fine and pulls hard again. I will never go to the stealership, this is like the tenth time ive heard of this kind of ****.

thebecwar

fordfan sounds right. Is your check engine light on? How many miles does your engine have on it? Are you noticing your oil level going down?

If the CEL is on, get the code read. It may be as simple as a misfire. And you also may be able to spend the money to just swap out the spark plugs.

If you keep up with the maintenance schedule and you've got less than 12,000 miles per year, or less than 100-150k total I'd be skeptical that you were losing compression. You could always check the compression on that cylinder. If the compression is good, then it's probably just a fouled plug.

If you're not noticing any oil burning then most likely you won't have enough seeping up through the rings to foul the plug. You may want to check your PCV valve. I have seen some cases where a stuck pcv valve lets pressure build up inside and force oil down through the valve guides, or up through the rings.

One last if... If the deposits on the plug are matte black not shiny black, then you have carbon fouling. That would tend to indicate that you aren't getting good ignition in that cylinder and lead me to guess that your COP or coil pack is starting to go, if it hasn't gone already.
[edit: Once you have the plug out you can compare it to the chart at http://www.verrill.com/moto/sellingg...colorchart.htm ]

And last but not least... Good luck, let us know how it goes.

mark

stacy

The check engine light was on and it was code 0305/0304 so we changed the coils and then noticed the oil on the tip of the spark plugs. the light came on again with the same misfire code. tel me what I i should do next please.

thebecwar

When you changed the coils did you put in new plugs?

stacy

No we did not replace the plugs. we cleaned them up and cleaned up the oil, ran it and still more oil at the tip of the plug where it sparks.

Good old Bill

I didn't catch what year and engine you have. Its nice to know this info just incase there is a paticular issue with an engine. Is there any smoke out of the tail pipe? What is the compression on this cylinder? In fact I would like to know compression readings of all cylinders?

stacy

Hey thank you! I have 160,000 miles and it is a 4.6L. i haven't got the compression reading because this truck is bleeding my bank account. How much should it cost to have a compression reading?

stacy

Also there is smoke coming out of the tail pipe. Not all of the time.

Good old Bill

Think its time to get your hands dirty. Necessary tools, spark plug wrench and compression tester. Buy the type that will screw into the cylinder not the rubber tipped type that has to be held in place. You will also need a friend and a service manual, I prefer Miller Lite. That type of manual is optional, but a Chiltons or Haynes is available.