Unless your spark plugs are leaking, then the oil that is accumulating on top of them is most likely not what is causing oil smoke out of your tailpipe (if you are indeed burning oil). If your engine is simply consuming oil, and you don't know where it's going, then a leaky valve cover gasket (where it leaks oil onto the plugs) could definitely be your problem. When spark plugs are screwed in tightly, though, if oil accumulates on top of them, not enough is going to get into the engine that would produce visible smoke out of the tailpipe. That would be caused by worn rings and/or valves/valve guides.
If all you have is a problem with oil on top of the spark plugs, be sure to try to fix it, and even if you can't get it to go away completely (I have found that getting those gaskets to seal perfectly can be difficult), be sure to clean off the spark plugs/wires from time to time. Used oil contains carbon, and this can cause a misfire--poor fuel economy.
Thomas
Tuesday, September 18th, 2007 AT 1:52 PM