HikinTech got me there with his suggestion that crankcase vacuum ressure should be in the range of a few inches of H2O vacuum; if not the air oil separator was shot/leaking internally.
I found that I had full intake vacuum in the crankcase......you had to pull pretty hard on the oil fill cap with the engine running to get the cap off.....and once off, it was a giant sucking like a vacuum cleaner ....until the crank case pressure equalized. Certainly not a few inches of H2O. I compared it using the palm of my hand as a vacuum gage/manometer.....to the X5 we also have and it was day and night.
Once removed and broken open, the old valve had a tear in the diaphram (to the atmospheric vent port) about 1/3 of the way around.
It's now apparent that the rough idle on start up was due to extreme lean condition as the entire crankcase was drawn to intake vacuum pressue level....once there, after about 1-2 seconds, the mixture returned to/near normal, and the idle smoothed out.
Thanks agian for your all of your great help and all the clues.
BTW: there's a great DYI on replacing the air/oil separator in Bimmerfest.
Mike