Fuel economy on Rangers virtually mirrored F-150s. The Ranger was dropped in the interest of CAFE, same with the Colorado. The Colorado in now back but Government Motors may have the insider CAFE standards. The only thing holding GM together is trucks.
Don’t look to Ford to bring back the Ranger, there was talk of it as a diesel platform, but with Tier 4 and the collapse of light truck diesels not so much.
Dodge was supposed to be installing a Penta V-6 diesel in Ram 1500’s