Scangauge tank mpg question

[dmerle]

When I last filled my car I did the fillip routine on my scangauge II. After I drove for about 15 minutes my current mpg was 37.5 but the tank avg mph was 35. Why wouldn't they be the same?

[2000mc]

if i'm only off for a few minutes, the current trip doesnt reset regardless of reseting the tank, off long enough it will. i'm not sure how long you have to be off for for the current trip to reset, but in my experience its independent of the tank reset

[gone-ot]

Originally Posted by dmerle

When I last filled my car I did the fillip routine on my scangauge II. After I drove for about 15 minutes my current mpg was 37.5 but the tank avg mph was 35. Why wouldn't they be the same?

...sounds like the algorithm that's "estimating" MPG is simply momentarily 'over/under shooting' as it does it's number crunching, usually the result of mixing integer and decimal numbers.