Originally Posted By: Nick R
Yeap that's the problem, the truck. The engine is not the problem here, so don't say that it is. The problem is the vehicle it is installed in.
The engine is a contributing factor. 4.0 is a fairly large displacement for a V6, and the design certainly isn't new. The SOHC variant has been around since 1997, and Cologne V6s have been around since the late 1960s. There are far more efficient engines out there. Keep in mind, many Duratec Ranger owners report getting 30+ MPG on the highway, and even my all iron pushrod 3.0 gets almost the same fuel economy in city driving as a 4.0 will on the highway.
However, the Ranger's design is ancient and that does play a major role in fuel economy. It was almost certainly the most aerodynamic pickup you could get in 1993, but definitely not anymore. None of the changes Ford has made since then have improved fuel economy (larger mirrors, broader/taller grilles, larger tires), and the truck has gained weight due to safety features and other additions.
But anyone who thinks they will get awesome fuel economy with a 4.0 Frontier or 4.0 Tacoma is kidding themselves too. Big displacement engines kill the fuel economy of small trucks across the board. If fuel economy is the main concern, I4s are the way to go.