The P1320 code is "Ignition Signal" and i have posted a URL at the bottom to link you to the information you need for that code. If the spark plug hole was almost full you need to take it to a mechanic to fix it because that can be a fire hazard. It could be from a valve cover leak to damaged pistons or the O-ring gone bad that is causing that oil leak. I hope this helps...
OBD2 - OBDII Code P1320 NISSAN - Ignition Signal | Engine-Codes.com