Can Code P0420 come on from oil in spark plug?

Question

I have a 2004 Altima, and I noticed my Check Engine Light was on, had code P0420, but I was changing spark plugs and noticed in the fourth one, oil was inside, I cleaned it out, replaced all spark plugs and put a new coil in the oil one, since it bacame soaked in oil and turned soft, unlike brand new one that is hard. Read some where that this problem can trigger that light, but after I changed it, light is still on....Will it go out after some time, or does this issue have nothing to do with the code? (Note only had code P0420) THANKS

Answer 1

I have not seen that. P0420 is usually for a bad catalytic converter

If oil is leaking inside the spark plug you will need to replace the valve cover assembly its about a $100 or so for the part