ive got the rec'd ngk. 20 notes for x4. i think iridium plugs would be a good investment. it happened again today. ive noticed a pattern here though, its only when you ask a lot of the ignition in 4th gear. with sensible use ie plenty of revs through the gears it doesnt happen. only when sat behind driving miss daisy and going for a lazy overtake (in 4th) im gonna investigate the plugs/gap em as appropiate in the morning. could overfuelling cause this. i know the on boost fuelling been correct has a detrimental effect off boost in terms of a/f.