My 97 4.6L expo. Started to misfire about 1 week back. The plug is front on the driver side. Changing it out, I noticed the highly feared "skushing" sound when sliding the socket down in the hole. Pulled it out and water on the plug. It is hard to know if it was in the cylinder or in the well. Last night on a late run to the Mart. It started the idling misfire again. This is my third new plug. The third plug I filled the boot full with Di. grease. What is my next step? thanks.