Loving our new 2008 FEH so far! We have 1400 miles on it and so far are averaging 35.5 MPG. We have not had to run the AC yet nor have we done any highway driving so we do not expect to keep the numbers quite so high for too much longer.

Here's my question....I have used the readouts to track my avg MPG. I have not reset this since I purchased the vehicle. If I do reset the avg MPG the next time I fill up, I am assuming I will only be tracking my MPG for the current tank of gas and will have lost the cumulative MPG. Is that correct? I'm wondering if there is any way to track MPG for each tank as well as for the cumulative history of the vehicle.

 

First of all, the computer doesn't maintain the full history of your gas mileage. It only maintains something like the last 1000 "data points" and no one knows what a data point represents. My guess would be about a minute since thats when the screen seems to update. That would be about 16hours of data.

So, you've already lost much of the "cumulative" data. Your best bet is to just track your mileage using either an excel spreadsheet or the database on this site...

https://www.greenhybrid.com/compare/mileage/

Besides, the computer isn't particularly accurate to begin with.

 

I agree with Tim. Put a log book in the console and keep at least the date, miles, and gallons used. This way you can enter it here or do your own spreadsheet.

I reset my AVG MPG and a trip meter at every fill-up. the computer is almost always 1-2MPG higher than what I calculate manually.

 

The MTE reading + trip odometer (assuming it was reset at fill-up) divided by 13.7 usually gives me surprisingly accurate MPG after about 200 miles, when the AVERAGE ECON seems to start scrolling off data. As an example, currently my AVERAGE ECON is at 46.2 MPG, nav ave. is at 46.4 MPG, SG is at 43.1 (with 7.5% fuel calibration) while the MTE is 304 with a trip odometer of 300.8 miles. (304 +300.8)/13.7=44.1 MPG, probably within 1 of what it actually is at this point.

 

I have found the NAV to be as close as any other method.
It does not keep much more than 1 tank of data, and sometimes less.
( I think time is a factor ) So I reset every fill up.
It usually reads higher than actual by about 2 MPG for me.
But since it is very consistent, and always high for me, I know what the car is doing.
The Nav ( or probably the instrument cluster too) will always be MORE accurate than the SG if you are using ethanol. Unless of course, like Carl, you manually adjust the SG.
The Ford built-ins are smart enough to automatically compensate for ethanol.
-John

 

I have hand calculated every single tank in the nearly 11,000 miles I have had my 2008, and found every single tank calculates out about 1/2 to 1 mpg LOWER than the readout. If I get a 35 mpg readout, I'm actually getting about 34