MPG Which one is more accurate?

[agood1]

The MPG rating on my Gryphon is averaging around 16. The one built in to my F150 averages around 14. Which one would be more accurate? The Gryphon seems to change allot more than the one built into the truck.

Thanks

[Jackpine]

This question's been asked before - my opinion is that neither are particularly accurate. I have an "Info Center" in my truck too, and in MY case, the dashboard value seems to be the most accurate. Others have said it's the Gryphon. I also think my dash value seems to be the more "rapidly changing" one. But, it's been a long time since I looked at either one. My new CTS has an "Inst MPG" which I look at from time to time, and it gives me an idea if I'm doing well or not. To calculate my MPG average though, I use the old-fashioned miles driven over gallons to fill the tank method. (I actually do this on a spreadsheet that I've set up to track towing MPG separate from non-towing MPG). Right now, in 3800 non-towing miles, I'm getting 15.0 mpg and in 1326 towing miles I'm getting 12.7.

- Jack

[Power Hungry]

Here's the one that works...



Seriously though, the one on the truck's display is usually a little low and the one on the programmer is usually a little high. One reason the programmer is off is the prevalence of 10% Ethanol nowadays. This causes a slight change in performance and affects calculated economy.

Take care.