The Tundra could use a taller rear end ratio but it’s still not revving very high while cruising at 70 because of the tall 6th gear. I think most of the reason for the bad fuel economy is the engine’s just inefficient. The 5.7 still uses single point throttle body style fuel injection instead of multipoint like most vehicles today. The Camry for 2018 had an EPA mileage jump from 32 hwy to 39 by incorporating direct injection, hopefully something like that is in the works for the Tundra. I think there’s some kind of new fuel economy requirements coming up so maybe that’ll kick them in the ass to fix it.
Tundras have multiport, they could end up going to Direct Injection but then you have carbon buildup issues like the Fraud Ecoburst engine which ended up going to a combo of multiport and direct injection in the 2017 F150 Ecoburst.
