Both could just be the bottom getting wet as you pull the plug out throgh the oil...
If you smoke a lot then I'd be inclined to say your rings are shot, possibl worse. Start with a compression test, and replace the valve cover and sprk plug well gaskets.
15.9 @ 86.7mph
Smooth idle? We don't need no stinking smooth idle.
Take out the sparkplugs and look down into the combustion chamber, U might need a flashlight and tell us what you see. also i think it could be a bad sparkplug seal, but that i dont think would cause the engine to run like shit.