2002Almera 1.5 Oil problem with spark plugs

My Almera started to struggle with acceleration and eventually refused to start. I checked the spark plugs and they had oil on the tip and on the threads. I checked the gaskets round the plugs and they seem fine. I refuse to believe that the pistons or piston rings can be worn on a Nissan this young (2002) so Im going to change the PCV valve on it.

The coils are fine cos I checked the spark plugs and change them to new. The car starts but the plugs come out with oil again. If I run the car, the oil will collect up and stop the plugs from firing again.

Is there anything else that can cause the oil to leak into the combustion chamber and onto spark plugs?

Can anyone help please?

Valve seals are commond for leaking if the PCV is blocked. Builds up pressure in the rocker cover and pressurises the seals, which leak oil down the valve and ino the combustion chamber.