Mileage Variance or Is It Just Me?

LivingtheDream

2009 LTV Serenity
Howdy... As I run through the miles on my LTV Freedom II Serenity on a 2008 Freightliner 3500 I am confused by the variance between the miles per gallon on the dash, and the miles per gallon calculated as the variance is most variable! I would think that the variance would have some consistency in it, but that does not seem to be the case.

I am over the 20K miles level so I would want to think that operations are reasonably stable. My driving habits are fairly consistent, too fast really for good mileage (70-75 mph in most cases, sometimes more but not often). Road conditions I know are variable, but that should effect both dash and calculation similarly.

When running my measures (have a spreadsheet with all miles and purchases since inception) and have begun to track the dash readout as well (because a concern with the inconsistency).

I have a variance of 1.9 mpg to 3.2 mpg, with always the dash reading more and the calculated mile per gallon less. My dash reading is usually 16.5 to 18.3 and my calcuation runs between 13.6 and 15.5.

Any thoughts? Do you have similar variances? Is it just me? .... :professor:


Thanks in advance for inputs...

LivingtheDream
Turn the Key and Smile
2009 LTV Freedom II 2008 Freightliner 3500 Chassis
2005 Cadillac CTS-V
 

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