see first posting dated may 1, 8:59 pm:car seen again for info up-date. eobd code p1159 manufacturers specific code aggrees with bmw code now also showing p272c additive f/trim 1 limit reached. eml light still coming on after a few days local driving and idle speed hunting from then on. engine parameters studied: both o2 sensors, fore and aft of cat, show in-activity until 3000rpm is reached when the fore cat only comes into closed loop. this activity immediately drops out again as the rpm is lowered below 3000. [note both o2 sensors have already just been changed for new genuine items] kevin apps has kindly already suggested the breather valve, often a problem on the v8s. i have the valve on order from bmw, primarily to help me identify the correct item during the coming induction strip-down. the list of possible causes of the above codes are quite daunting, i need to learn fast on this "valvetronic" thing so further suggestions would be much valued. regards to all, peter.