Playing Devil's Advocate Fuel computers are usually off, did you do any actual calculations?
No. And generally, the reason people find fuel computers are off is that they don't reset them in a way that properly correlates to when they fuel up. If you reset at fill-up, run several tanks through, and are able to truly accurately get back to the exact same fill point, you'll find you get a pretty good result. Most people don't do that. The less fuel you run through, the more likely small differences in what you put in, where the nozzle shuts off, etc will make a much bigger difference. Fuel computers are also off in that they calculate for the full duration they're calculating, when the driving you're doing is specific -- so estimates of fuel remaining tend to be way off because you drive differently as you get low on fuel. To make it worse, different manufacturers calculate differently. My former car, a Subaru, seemed to calculate mileage and DTE based on a rolling 10 mile or so average so it could be way off what you would expect. This Ford computer seems to be more rigid, calculating actual fuel use by actual miles since you pressed the clear button on that trip -- which is both good and bad. It means if you don't hit the reset fairly often, your calculated number is averaged over a very long period and will tend toward median -- which is misleading in terms of calculating DTE for right now.
Edited by FirefighterGeek, 23 August 2017 - 07:49 PM.