this has been resolved. it turns out that in it previous life at sometime a PO dicked with the TPS settings! the blue paint was missing which was a clue and when i pulled the boot i could see that someone had punctured the w/r wire. long story short they had done a zero=zero using the wrong target numbers.
fortunately this was discussed quite a while ago here :
https://www.bmwsporttouring.com/topic/77572-tps-alignment-idle-speed-adjustment-beyond-zerozero/#comment-883795
i adjusted the tps from its zero setting to the suggested setting of 250mV and the reset the butterfly stop to 370mV. If i understand it correctly 911 has a feature to do this without mucking it up. i assume the bmw diagnostic can do it too. theres really no reason to touch it unless you repair the throttle bodies or your tps dies.