I had the notorious "mis-fire" in cylinder 4 on my 00 S Type 4.0 - I purchased a COP tester - Matco COP963 (one tool I can't live without!) to check all COP's and diagnose. Yes, the bottom of the COP in cyl 4 had oil in it. It's winter time and can't get to changing the spark well gaskets until the spring so I placed black RTV sealant around the inner side of the spark well, where the spark well gasket is and let it dry for about an hour and reinstalled the COP - I checked the new COP the other day and it was bone dry in the well. I plan on doing this to all the spark wells in the spring when I change the spark plugs and all cam gaskets - both sides as a bit of extra insurance.

 

Awesome quick and affordable fix. Thanks.