Stop in for a cup of coffee

@Just Ron

Another issue that may or may not be related. The PCV valve rattles.....

So, talking this over here at work, we had a discussion about a bad ring/broken ring/up side down ring possibility. The thought was oil is getting into the chamber and fouling the plug...the cylinder then no longer fires and gas washes the plug clean except where the electrode and ground strap are partially guarded from incoming fuel...explains the oily residue in the exhaust pipe also. At higher RPM maybe the cylinder works...unsure. The rattle from the PCV valve could be combustion pressure getting into the crankcase....rattle (due to pressure change) each time that cylinder comes up.