We took our 2001 Kia Sportage to Advance because it was idling and running rough. Thier computer shown that number 1 cylinder was miss firing. I had replaced spark plugs and then the wires over a year ago for the same problem and after the wires were replaced this fixed the problem. To day I changed the spark plugs and while changing I noticed alot of oil on the last plug near the firewall. It ran fine for 10 miles the the rough running developed again. This car has 128,565 milles on it. I figure this spark plug is fould out again. What does this excessive amount of oil mean or possibly mean.