the previous emissions test i had to send my MB guy with the car to emissions garage to lean out mixture to make it pass (and promptly readjust so it would drive OK)
but now im emissions EXEMPT
i did not adjust the mixture myself at all as thats really beyond my skills level
the voltage does change and go lower, just not above .351, i will retest this on an upcoming longer trip and report results, the car uses LOTs of oil 1qt/300 miles
so id guess the O2 sensor is plugged up with oil residue and not working 100%