There really shouldn't be any oil on your spark plugs under normal circumstances. Usually, on newer vehicles, I suggest new plugs and wires (a tune up) around 100,000 miles. However, if there is a problem before that - such as abnormal noises or the presence of oil or other fluids - it is probably a good time to have it looked at by a professional. Check out Ask Patty's list of female friendly shops in your area.
〉 Answered on Aug 28th, 2008 by Suzanne Grego, Technician at City of Philadelphia Fleet Management