Originally Posted by r1ch999999
Do you guys calculate it yourself or let the car do it?
I use the display, but I've checked it. I put all my gallons into a spreadsheet, and I check the odometer with the mileposts on the side of the road, although so far in the Focus I've really only done 1 long test over 60 miles.
I also might add that I have my tires @ 38 psi - not suggested if you live in rainy areas or are not a defensive driver. I am careful with my cars: my last car was a Dodge Neon (stick)that I bought new and have 450,000 miles on it with the original (either) rear or front brakes.