Evanston WY to Cheyenne across WY on 80 with 75mph tailwind 18mpg in my 94.
Cheyenne WY to Evanston across WY on 80 with 75mph headwind 4mpg in my 94.
Normal conditions, sane highway driving, 12 is normalish.
based on that fuel pump picture I'd definitely replace the fuel filter while the line is de-pressurated. Also the fuel regulator.
https://forum.ih8mud.com/threads/fuel-filter-replacement-complete.1025600/