MAN ----ill bet you.ll never ask a question like that here again---ha ha ha
its CALLED MOISTURE......i beleive nissan recalled some harnesses for this prob.................take your plug wires off and spray them with wd40'''
take your plugs out if you can and clean them up too....
has it rained hard in the last couple of MONTHS????
happens to alot of people ....check the area were the plugs go to the cap ---some time the cap gets a hair line crack from over tightening ,,,,,it gets hot on the inside and draws moisture .....its alot worse when it has rained
sounds like your getting a arc....check the inner cap diode..too
ALSO PUT three containers of heat ...its a moisture remover from fuel....maybe thats a prob

NEVER GET GAS AT A GAS STATION THAT IS GETTING FUEL THEM SELVES _____IF YOU SEE A GAS SEMI AT A GAS STATION ___DO NOT GET FUEL FOR AWHILE ....the semi kicks up mad setiment in the underground holders...
you also will get a higher concentration of inner water .....which really makes you think you have huge PROBS but its just WATER=====
I HOPE THIS HELPS -------happy to help