Number eight cylinder misfiring water on top of spark plugs

Even though I have found a lot office oily water in the shaft where the number eight cylinder spark-plug is. The engine is not over heating. Neither have I seen a white substance under the oil cap.

No vapor is escaping on the passenger side. Neither have I seen bubbles coming up in side the coolant reservoir.
Maybe I did not drive my car for too long. It does not misfire continuously but intermittently. Sometime is running smooth and the engine line blinks while other times the light is on constant. And. The car looses power in addition of misfiring.
I appreciate your help. I surely hope it is the radiator that can be easily fixed.

What is your opinion?