"O2 sensor adaptation limit" fault codes
 

Any thoughts on causes? I'm getting the code for both bank 1-3 and 4-6 so I'm guessing its not actually the O2 sensors.

Symptoms: Occasional stalls at stop signs/lights, gas mileage seems off. otherwise runs very well.

Other stuff: 2002 X5 3.0l, 95k miles. Replaced the Oil Separator last year has run fine since (but that's another story). Winter in buffalo - outside temps between 0-40F. No other codes.

thanks!

Try checking the rubber boot on the throttle body for leaks. Common enough problem.

yup sounds like a vacuum leaks

I had the same codes on my 3.0 and it ended up being the O2 sensors. The service interval is 100k and you are almost there so I would go ahead and change all four. You will save a lot of money on the sensors if you buy them from Bav Auto instead of the dealer. Mine ran fine with the codes for a few months and then started misfiring until I changed the sensors.

O2 sensor adaptation limit fault - solved
 

Checked for vacuum leaks & found none. changed the upstream O2 sensors - problem solved. $140 for 2 bosch sensors, $20 for the special tool (worth it), 30 minutes to R&R. Thanks for the input.