You definitely need to reset adaptions.

My downstream sensors both under 15,000 miles old died and gave me one drive error. When I replaced and cleared the codes I drove about 100-200 miles and I got another O2 based code. Reset adaptations and no code for a while.

I think I might have a minor exhaust leak maybe at the SAP valve I really hope not at the manifold that's not a fun job. That could through off the math just like unmetered intake air. Unmetered exhaust may be causing some of our weird O2 sensor readings.

I replaced my post cat sensors with Bosch and saw an immediate difference in how they performed. I need to do the same with the pre cat sensors. I would not use non OEM again. I bought a set maybe as a social experiment that were German made knock offs. $44 for a PAIR. They seem to work but one outright failed after half a year or so (they replaced no questions asked under warranty). That said I still seem to get these random odd lean errors after a few months and very likely from the non OEM pre cat O2.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)