2004 P71 4.6l
OBD2 says misfire in number 7.
Took off coil pack, saw oil inside bore where spark plug is, wondering where the hell the oil came from... Anyone had this problem before?

Thanks all,
Tom Mead

 

Some coils are solid and some are oil filled for 'cooling' my 6 volt + ground 1930 Ford Model 'A' has an oil filled coil. And it hangs on the firewall up side down. And it doesn't leak oil. Even if all the oil leaked out, the coil, me thinks, may still work. This is dielectric oil, otherwise I'm pretty sure the windings would short out from the factory.


Miss firing; Ford boots from the coil to the plug are $5.00 each.

Ford miss fires many times are caused by a spark shot sideways and going to ground 'in the void' of the head and not at the spark plug's tip.


The silicone coated spring wire from the coil to the plug usually is conductive and if making a solid connection to the top`o-plug is not troublesome.


Check the boots for pin holes, tears and burned or grey carbon marks or hardening and crumbling of the rubber.


It's tough but maybe a mirror and a flash light will show the 'strike' in the metal where the spark went to ground down in the spark plug's void.


Now, strangely enough, my miss firing 1997 Ford Expedition out in the drive way with almost 300,000 on the clock starts instantly and runs great when it's -18 degrees outside. Once it warms up it runs crappy. So what happens?


Do the windings expand within the coils as they warm? Do they arch out? Break continuity? I highly doubt it. Do these things have a transistor in the solid, molded guts? Naaa, no electronics. Just a pipe dream.


Why does it run good when it's cold? Richer mixture? Cold start valve. Some air mass signal? Cold air signal? Bad oxygen sensors? Timing?


If any of you gear heads have any ideas sound off.


skip.

 

Most likely the oil is coming from a small leak on the valve cover gasket.

 

Yes! Although I haven't seen so much oil that it got into the boot<->sparkplug connection, I have seen oil down in the hole and on top of the intake manifold<>block mating surface. In my case, it was an original intake on the 2002 4.6 (Grand Marquis) that caused it, presumably it was either not sealing good, or the oil passage itself was cracked. From what I recall, there's an oil passage on the back of the intake manifold that jumps oil from one head to the other, next to cylinder #8. The oil I saw on the surface was sitting back there around cylinders 7 and 8. I never performed extensive analysis on the old intake, I just replaced it. One thing I can tell you though, is that at 71k miles when the car was bought, one of the coil packs on that side had already been replaced. I'm still working on the issue I described in the "Loud top-end tick" thread I started in this forum... the next time I open her up to put in more work, I'll let you know which cylinder has the new coil pack, even if only for "anecdotal evidence".

And for the sake of full disclosure/background info, the reason I replaced the intake manifold (a little after 80k miles, if I remember correctly) is because the cooling system ran dry, overheated, and caused the intake manifold to develop a small crack on the back of the coolant passage on the driver's side. It leaked coolant down into the engine's "V" as a result. Again, because of the oil leak and the coolant leak, I replaced the whole thing with the Dorman aftermarket unit.

Hope that helps!

 

A scan-tool would tell you quite a bit. Fuel trims, O2, MAP/MAF readouts, etc. are all given in the live PIDs. Any of those things you mentioned (i.e. O2 sensors, or a MAF sensor) could theoretically cause, or contribute significantly to, the problem you described.