Several members have had this problem disappear with replacement of the MAFS. Have your tech. check them. Here's some info from another post regarding the MAFS. This was in reference to a loss of power, but the info may apply here as well:
"Air mass meters or HFM 5 can defininetly cause a problem with lack of power even without storing fault codes. The best way to check them is in the diagnosis function in BMW's tester under diagnosis requests,without nominal values. They should read a voltage of 1.09-1.16v @ idle but the important thing to check for is the deviation between left and right, this should not exceed 5-6mv or 0.05-0.06v. If there is a difference higher than this or the voltages do not fluctuate slightly then you possibly have a problem with one of the meters. Normally the one with the lower voltage or the one with the frozen reading is defective, the difference in voltage can also be influenced by the flow rate of the airfilter so do the test with the filter fitted and without to rule out a blocked fresh air intake.
Mixture adaptation refers to the amount of secondary or unmeasured air found in the intake plenum and the spec of 15% refers to the adaptive correction factor the DME employs to counter-act this, if you have a high Multiplicative mixture adaptation this means that your intake is sucking in unacceptable volumes of unmeasured air- leaning out your air fuel mixture and then enriching it to counteract surges in power and promote protection of the CAT.The air mass meter only "estimates" with a large degree of accuracy the amount of air entering the plenum chamber thus the added telemetry function of Multiplicative mixture adaptation."
Linear Mode
