Yesterday I checked the mileage on the same 160 mi. I-5 roundtrip done last year, to the Roseburg Graffiti weekend.  100% gas was in the tank.  There was a little more weight, with a passenger friend, plus tool box in the bed.  Only came up with 18 mpg, compared to last year's 18.7.  Ambient temps were cooler than last yr., on both legs of the trip, so engine was only averaging about 160 degrees.  The 20 mpg target isnt going to happen.   

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.