On the very first start of the day, our 528i idles roughly until warm, and if you drive it before it smooths out the car continues to get worse until the check engine light comes on, if you turn the car off and then back on after the light comes on it idles/runs great and you would never know there was a problem. All progressive starts through out the day are fine, with the car acting beutifully. What on earth could be causing this, the car has done this for quite a while BTW. thanks R