I'm in the market for a new truck. I was serious about a Tacoma then I got to comparing what matters; gas mileage and cabin space. From my research, the Tacoma 4-door, 4x4 V6 gets 18-21 highway mileage. The F-150 seems to be pretty close if you drive it right. I'm wondering how much difference in mpg there might be between the 3.7 V6 and the 5.0 V8? I have a 26 mile commute into work which consists of about 80% highway and 20% in town driving. Who can help me with my decision?
The Tacoma is reputed to be the most efficient of the midsize trucks, and the 4 cylinder 2012s are averaging 18.3 mpg on Fuelly so far. Haven't checked the current F150s (there are a LOT of configurations), but I doubt you'd be able to match the Tacoma mileage. The F150 is a full size truck -- it's not built for economy.
Some Taco owners are reporting 23 and 24 mpg averages -- I'm trying to figure out how they're doing it. Maybe they're only driving downhill away from the wind.
The mileage difference between a V-6 and a V-8 for the same chassis, drag, weight, etc. should be almost the same. The difference you'll run into is that the V-8 will require slightly more maintenance costs but will likely have a greater life expectancy due to the engine being run at highway speeds using a lower percentage of the engines available horsepower which effectively means that the engine doesn't have to work as hard and therefore has a longer life expectancy.
All bets are off if you're considering the EcoBoost engine, from what I've seen that engine is significantly more fuel efficient than other powerplant options.
My neighbors had two GM trucks, the husband had a V6 and the wife had the V8. Even though she had a lead foot, she got much better gas mileage than he did so things aren't always as easy as they seem. I don't recall any mention of higher maintenance costs.