I found 3 of my spark plugs have oil all over it.
Is this problem coming from the gasket?

thanks.

 

Hayne's Manual: "Oil is leaking past worn valve guides or piston rings into the combustion chamber."

That's gonna be a costly repair job.

 

If it's oily on the outside of the plug, then it's the o-ring seals on the valve cover. Not a big problem unless oil is really pooling up at the bottom of the spark plug tube. Front valve cover is easy to remove, but rear requires removal of the intake plenum.