Need help 5 of the spark plugs look ok with the white or gray color tip but there's one spark plug on cylinder 6 by the throttle body is totally black on the tip like its foul. Upon inspection of cylinder 6 through that small spark plug hole is wetness an as I touch it. It smell like fuel. Am I experiencing a fuel injector leak on this cylinder an if so does these v35 250gt skyline use the Same fuel injectors. Car starts fine but idle rough at low rpm, black fire also strong exhaust fumes an lack of power am experiencing