I filled the tank yesterday, I had a few hundred miles to cover to make some estimates. The "feed me" light was on when I left the house I drove to the gas station which was about 4 miles. It took 24.257 gallons to fill it up. I had a few stops around Sacramento to make about 30 miles, then I drove up to lake tahoe, about 60 miles, Then back to Sacramento, 60 miles. Then to Stockton, 45 miles, Tracy another 20 miles. Then on to San Jose another 75 miles, and finally to Gilroy. Then back home about 170 miles. The ''feed me" light came on again about 7 miles from my house, so I figured I used the 24 gallons that I put in.
So, that was a total of 491.3 miles on approx. 24.25 gallons. It took me a few hours longer than it should have because I was posting on the org while I was typing up estimates in the truck
I had the cruise set at 69 mph, running the looney tune from vivian. Hand calculated, 95% freeway driving.