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Old 09-06-2019, 06:03 PM
RPsX5d RPsX5d is offline
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Location: Bay Area California
Join Date: Nov 2010
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Mein Auto: X5 35d, MY2011 150,000 mi

Quite possible I don't fully understand how these things work.

In my case, since the car was new (4 miles on the odometer) up until now (9 years later and 150,000+ miles), the manual mpg pretty much stayed the same - about 22.5 mpg.

To me that means the sensors, the computer control, injectors, etc etc have not shifted/changed much.

For the first 110,000 miles or so, both indicated mpg and manual mpg matched . . . meaning the K-factor setting done at the factory was pretty close. Then the indicated mpg started to drift down, while the manual mpg remained constant.

If the electronics/sensors used to compute the mpg is different from those used to operate the vehicle, then I can understand your explanation - the electronics/sensors used to operate the vehicle remained constant but one or more sensors unique to the indicated mpg electronics started to drift and is now causing this difference.

I find it hard to believe there is a completely different set of electronics/sensors to compute the indicated mpg.

I suppose best to stick with manual mpg . . . no ambiguity about that figure!
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