The mech. says it needs 6 new spark plugs (these were replaced one month ago), and 6 new coils (one was replaced about three months ago). As the spark plugs are oiled up (according to the Mech.), I'm wondering if the Castrol Edge 0-40w oil is too thin for my car, and if it was this that caused the misfire code on cylinder 2. The spark plug on cylinder 2 was like new as if it had never fired. The front crankshaft seal is now leaking oil quite badly. I did check with the E46 forum, and with Castrol before using this oil as the car has done about 80k recorded miles. Has anyone got thoughts on this, and the best oil to use? Thanks Are.