The engines on our Frontys are reliable, but old-school. I have a new '16 2.5L KC with 5-spd. At a steady 70 on I95 (which is the posted speed where I live and commute) I have put almost 3K miles on the truck and am averaging 23.5 mpg overall. On the rare occasion I lead-foot it and do 75-80, my mileage will fall to about 22mpg for that tank.
Not much else that can be done, except as others have mentioned, don't bury your foot in the throttle.