hey tell your bimmer dealer to lay off the hardware and just swap out the damn sensor....when they look at you and say huhh ask them what your oil looks like if they say like we just changed it then none of these other recreational activities they are engaging in are worth your while...had and seen similiar problem on other bmr's in past..matter of fact have or had same one on the 02 certified i just bought it's most likely the sensor....let me know how it goes and good luck...j.lee