my jeep is missing, last time it did that it was bc oil was leaking into the 3rd cylinder and fouling out the spark plug, soo i replaced that spark plug and ignition coil, well it's doing it again only a few weeks later, i hate to put my jeep in the shop but if it's what i have to do then i'll do it...however, what is the cause of the missing? i know oil has to be leaking onto the spark plug somehow...please help, its getting worse and worse.