MPG indicator question

[bsl2ck]

Does anyone on the forum know the period over which the average mpg indicator average is calculated? I know that on my 15, or so, mile trip to work, it can change almost 1mpg or more if I sit in traffic for a long time (those instant mpg 0's add up). So the average can change dramatically over the course of a tankful of gas. This morning I found that the average on the dash was over 1 mpg higher than the calculated mpg based on miles travelled and gallons used (determined at pump by gallons to fill and miles travelled since last fill-up). Is this what you folks see as well?

Thanks

[rbarrios]

its determined since it was last reset.
so if its never been reset- it will average over all those tankfuls...
if it was reset at last fillup- its based on that amount of gas used.

on the Impala- which has the DIC (my TB does not)...
when I refuel the tank, and reset....... I leave the DIC on the screen that shows AVG MPG....
as you leave the gas station- this number starts going up.... few blocks later- lets say im at 7.8, 7.9, 8.0 mpg and I come to a stop at a red light, and I sit there idleing, this number starts to go.. 8.0,7.9.7.9,7.7 as long as I sit there... start moving at green light and that # starts going back up...

[parrothead]

its determined since it was last reset.
so if its never been reset- it will average over all those tankfuls...
if it was reset at last fillup- its based on that amount of gas used.

on the Impala- which has the DIC (my TB does not)...
when I refuel the tank, and reset....... I leave the DIC on the screen that shows AVG MPG....
as you leave the gas station- this number starts going up.... few blocks later- lets say im at 7.8, 7.9, 8.0 mpg and I come to a stop at a red light, and I sit there idleing, this number starts to go.. 8.0,7.9.7.9,7.7 as long as I sit there... start moving at green light and that # starts going back up...

:iagree:

You can reset the DIC (drivers information center) going to avg millage and holding the bent arrow key in for a few seconds on the steering wheel. Same goes for resetting the trip 1 and trip 2 millage counters. I personally find it a bit depressing to have the instant millage counter on(Esp when I see 9mi/gal upon start up from a dead start) so I only press the avg millage every so often.

[bsl2ck]

Thanks guys, I'll give it a try.