I've done a lot of miles in diesel-powered Range Rover Sports. In 2016 I ran a handsome Montalcino Red Sport HSE Td6 with the 3.0-liter turbodiesel V-6 under the hood as part of the MotorTrend test fleet. And I loved it. Sure, it was slower than the punchy 510-hp Sport V-8 Supercharged I'd previously had. But the Td6 was a lovely, long-legged cruiser, the torquey oil-burning V-6 growling as the Range Rover devoured the miles on road trips through California, Nevada, Utah, and Colorado. And it routinely returned 25 mpg or better on a long run. Land Rover no longer offers diesel engines in any SUV in its U.S. lineup, not even in the chunky Defender. Jaguar Land Rover had…