Getting Terrible Mileage. Any Ideas?

Advice Needed
21

What tires are you using, and what PSI are they set to? I have a 2022 Expedition Timberline with BF Goodrich KO2s set at 45 PSI. I get around 17 mpg at 80 mph, but if I stay under 70 mph, I can get 20-22 mpg. When I first switched from my Goodyear Wranglers to KO2s, they were inflated to 35 PSI, and my fuel economy dropped by 3-4 mpg. After bumping it up to 45 PSI, my mileage improved, though the ride is a bit bumpier.

Have you replaced your air filter recently?

22

I’m running Toyo Open Country A/Ts, size 275/55 R20, at 50 PSI. They’re 10-ply tires, but I didn’t realize that when I bought them.

23

Just finished a 1,400-mile road trip on I-90, driving between 75-85 mph. I averaged about 73 mph and got 19.6 mpg. Took another 240-mile trip today, speeds between 55-75 mph, and averaged 20.7 mpg. Stop-and-go driving in town usually gets me around 16-17 mpg.