Code po301 knocking noise when starts on 2004 Ford Explorer

there was some oil and water in the valve cover cap. I have blow by oil getting sucked in the intake manifold. Gas mileage plumage. Rings? cracked head? what should I do? Code po 301

Asked by for the 2004 Ford Explorer
Have compression checked on passenger side front cylinder. That spark plug should be wet when removed, is it?