Increase in gas mileage?

Did the caller get new tires?

The Brothers don’t reply here, at least they don’t under their real names.

I had a similar experience with my 2002 Subaru Impreza with 180,000km. As I drove west from Indiana, my mileage (typically the Transport Canada rated 8.5litres/100km) got steadily better, until in Utah, it peaked at about 4.7 litres/100km, better than a Toyota Echo! (BTW, a LOWER number is better…less gas for 100km, about 60 miles)

I checked my tire pressure and it seemed as though the improved mileage was related to the drop in atmospheric pressure as I climbed over the Rockies. By the time I got to Eugene Oregon my tire pressure went from 40 PSI back down to 32, an my mileage was back to normal.

I shoulda stayed in Utah!