Oil leaking in spark plug; does it harm performance/MPG?

[donutDrift]

While changing my spark plugs I found the 6th cylinder plug submerged in oil. Also, the coil pack tip seemed to have been exposed to oil.

My question is if having oil leaking into the plug will hurt performance or gas mileage? I know it will consume more oil which these cars are already notorious of doing. Should I urgently swap the valve cover from Z1 and is it recommended to go ahead and swap both of them?

Should, when I replace the valve cover; buy a new spark plug and coil pack?

Thanks for any input.

[amc49]

Yes after a point. Engine begins to miss. Oil by itself doesn't carry much current but when dirty with carbon and dirt in it does well. The spark at some point will find it easier to jump around the side of plug on the outside since it no longer has to jump through air, the oil on plug porcelain burns then becomes even more conductive. The higher the level gets on coil the more likely to ruin it. Low enough you can often recover both the plug and coil, I've done it more than once.

You generally replace the cover gasket, not the cover itself unless damaged in some way.

[donutDrift]

Yes after a point. Engine begins to miss. Oil by itself doesn't carry much current but when dirty with carbon and dirt in it does well. The spark at some point will find it easier to jump around the side of plug on the outside since it no longer has to jump through air, the oil on plug porcelain burns then becomes even more conductive. The higher the level gets on coil the more likely to ruin it. Low enough you can often recover both the plug and coil, I've done it more than once.

You generally replace the cover gasket, not the cover itself unless damaged in some way.

I guess I'll go ahead and do the repair. Also, I forgot to mention that I have a G35 Coupe; which is why I'm having to switch the whole valve cover. I've read that when oil is found in the spark plug crevice; replacing the gasket won't fix the problem.