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Old 09-08-2019, 10:28 AM
RPsX5d RPsX5d is offline
Officially Welcomed to the 'Fest
Location: Bay Area California
Join Date: Nov 2010
Posts: 1,240
Mein Auto: X5 35d, MY2011 150,000 mi
Thanks again . . . now everything is clicking into place nicely . . . at least for now I am comfortable to be in a watch-and-see mode . . .

When I first noticed this drop in indicated mpg, none of my searches yielded anything definitive, I did post this question here . . . thinking one or more sensors may have gone bad and as a result, the computer has shifted to a different part of the air/fuel ratio map . . . with no fault codes, I didn't want to do anything . . .

As always, never skip the obvious and simple checks . . .

BTW O2 sensor . . . what's the service life of these sensors? Mine is a bit over 100,000 miles now. I view these O2 sensors, like the NOx sensors, as maintenance items.

On our M57, there is only one O2 sensor - correct?
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