There is excessive fuel not getting burned and finding it's way into the oil. Your going to want to change that oil. The fuel will act a s a solvent and ruin the motor.
Why just change one plug?
What did they look like, black and sooty?
All the same?
Did you pull the distributer cap off and check it?
Are the cold days also damp? If so I would lean towards ignition wire or distributor related problems.
Sunday, January 7th, 2007 AT 9:33 PM