Vehicles with the Worst Real-World MPG

Since 2016, we’ve put hundreds of cars, trucks, and everything in between through our real-world highway fuel-economy test. We conduct every test on the same 200-mile out-and-back loop of highway and at as close to a 75-mph cruise as traffic will allow. The results are occasionally surprising but always illuminating. The highway fuel-economy estimates on window stickers come from EPA testing, in which the average speed is 48 mph. We think our test gives a better picture of how cars respond to the kind of driving Americans actually do.

And we test vehicles the EPA doesn’t. Pickups and cargo vans with a Gross Vehicle Weight Rating (GVWR) of 8500 pounds or more and passenger vehicles such as SUVs with a GVWR of 10,000 pounds or more are exempt from EPA testing. It’s little surprise that those hulking vehicles feature heavily on this list of least-efficient cars.

2020 Ford Transit: 16 mpg

EPA highway estimate: Not rated

Model tested: 2020 Ford Transit 350 Crew AWD High-Roof 3.5TT

The high-roof Transit 350 is a mammoth automobile, with a roof just a few inches shorter than a standard basketball hoop. The Transit is surprisingly pleasant to drive, but even on the mostly flat ground where we run our highway fuel-economy test, the nearly 6000-pound van’s twin-turbocharged 3.5-liter V-6 works hard to motivate it. In 200 miles of 75-mph cruising, the Transit returned 16 mpg. The Transit’s large tank means it can go 400 miles at that rate before running out of fuel, which is some consolation. As is the Transit’s incredible 300-cubic-foot cargo hold.

2020 Ford F-350 Super Duty: 16 mpg

EPA highway estimate: Not rated

Model tested: Ford F-350 Super Duty turbocharged 6.7-liter diesel V-8

The EPA doesn’t provide fuel-economy estimates for heavy-duty trucks, so you could say we’re doing their work for them by running fuel-economy tests on all the HD trucks that pass through our parking lot. Many of them, including this diesel-burning, 6.7-liter-V-8-powered F-350, cluster around the 14- to 16-mpg mark. Even though the F-350 is featured on a list of vehicles with very bad fuel economy, it’s more efficient than several of its direct competitors. Plus, depending on its specs, the F-350 can tow up to 20,000 pounds. In fuel economy, as in everything else, context is key.

2019 Ram 3500 Mega Cab DRW: 16 mpg

EPA highway estimate: Not rated

Model tested: 2019 Ram 3500 Mega Cab DRW

In terms of towing, Ram has built the ultimate truck. The Ram 3500 Mega Cab we tested in 2019 was equipped with a 400-hp turbo-diesel 6.7-liter inline-six that makes 1000 lb-ft of torque. It’s a lot of pull, and that’s why this heavy-duty pickup can handle up to 23,000 pounds with a conventional trailer. And with 2019 also representing the first year of a new generation, the Ram rode on a new frame with a restyled body (though the cab and door panels were carryover). None of those updates affected fuel economy on our loop. Sixteen mpg isn’t much to celebrate, but it’s not bad for a truck this size. That number is sure to fall, though, when the 3500 is towing a large trailer.

2018 Toyota Sequoia SR5: 16 mpg

EPA highway estimate: 17 mpg

Model tested: 2018 Toyota Sequoia SR5 4×4

Toyota’s massive Sequoia is powered by a 381-hp 5.7-liter V-8, the same engine in the Tundra pickup. It’s paired, as in the Tundra, with a six-speed automatic transmission. The Sequoia earned a mere 16 mpg on our highway test, making it among the few tested vehicles listed here that is not a heavy-duty truck. Engines are good for more than fuel economy, though, and the Sequoia makes good use of its thirsty mill: The truck launched to 60 mph in a sprightly (for its size) 6.4 seconds during our most recent test.

2017 Ford F-450 Super Duty: 16 mpg

EPA highway estimate: Not rated

Model tested: 2017 Ford F-450 Super Duty Diesel 4×4 King Ranch

Ford’s F-450 is a beast, with a turbo-diesel 6.7-liter V-8 and a 32,500-pound maximum trailer rating. We weren’t towing anything when the F-450 managed 16 mpg in our 200-mile highway test. In mixed driving conditions, we recorded 13 mpg. Those numbers don’t tell the whole story, though. The F-450 is blessed with a massive 48-gallon fuel tank, so even at 16 mpg, you can go 760 miles between fill-ups. That’s luxury.

2017 Chevrolet Silverado 3500HD: 16 mpg

EPA highway estimate: Not rated

Model tested: 2017 Chevrolet Silverado 3500HD LT Crew

The EPA doesn’t test heavy-duty trucks (those with a Gross Vehicle Weight Rating above 8500 pounds, specifically), and we didn’t have high hopes when we took a Silverado 3500HD with a Duramax diesel 6.6-liter V-8 out for its exam. We wouldn’t go so far as to say that the 3500’s 16-mpg effort impressed us, but that efficiency, such as it is, is at least on a par with the fuel economy that more run-of-the-mill trucks and SUVs returned. A Silverado 2500HD with the same engine earned a credible 19 mpg in our highway test.

2020 Jeep Gladiator: 15 mpg

EPA highway estimate: 22 mpg

Model tested: 2020 Jeep Gladiator Mojave

The Jeep Gladiator’s tall, flat front end puts it at an aerodynamic disadvantage. But nothing else on the road is quite like the Gladiator, with its removable roof and doors, useful truck bed, and Jeep good looks. In our hands, the Gladiator with a 3.6-liter gas-powered V-6 and an eight-speed automatic earned 15 mpg on the highway, 30 percent worse than the EPA’s 22-mpg estimate. The Jeep is also available with a turbo-diesel 3.0-liter, but we haven’t put put that version through our gauntlet of tests yet.

2019 Mercedes-Benz Sprinter: 15 mpg

EPA highway estimate: Not rated

Model tested: 2019 Mercedes-Benz Sprinter 3500XD 4×4 V-6 diesel DRW

Depending on who you ask, the Sprinter van may be considered one of Mercedes’s greatest accomplishments. The S-class is more luxurious than some private jets, and the hot-rod E63 Wagon is perfection incarnate, but can you live in either of them? Those who choose to bunk in the dual-rear-wheel- and four-wheel-drive Sprinter we tested would be sharing space with a turbocharged 3.0-liter inline-six consuming a gallon of diesel every 15 miles on the highway.

2019 Mercedes-Benz G-class: 15 mpg

EPA highway estimate: 17 mpg

Model tested: 2019 Mercedes-Benz G550

The G-class entered a new generation in 2019 after going almost unchanged since its introduction in 1979. There is lots to like about the new G, but improved fuel economy isn’t on the list—at least not according to our testing. The 2019 G550’s turbocharged 4.0-liter V-8 carried over from the previous generation (though the nine-speed automatic transmission is new). The G550 earned an unimpressive 15 mpg in our testing, matching the result of the previous gen’s G63 model (more about that later). The EPA estimated that the G-class would earn 17 mpg on the highway, better than the 14-mpg highway estimate for the previous-generation truck.

2017 Mercedes-AMG G63: 15 mpg

EPA highway estimate: 14 mpg

Model tested: 2017 Mercedes-AMG G63

The G63 has the dubious honor of being the only light-duty vehicle (technically, of course) to earn less than 16 mpg on our highway fuel-economy test. This previous-gen G-wagon marries rectilinear 1970s military-vehicle styling with a massively powerful twin-turbocharged V-8. Precisely zero people in C/D’s office anticipated that the G63 might deliver anything higher than subpar fuel economy. Sure enough, it didn’t, although it did improve on its EPA highway estimate by 1 mpg.

2017 Nissan NV3500 HD: 15 mpg

EPA highway estimate: Not rated

Model tested: 2017 Nissan NV3500 HD SL High Roof

No one buys heavy-duty cargo vans for the fuel economy, especially not in ungainly and aerodynamically challenged high-roof configurations. Even without the available seating for 12, the Nissan NV3500 we tested tipped the scales at 6316 pounds. That’s a lot for the 3500’s stout 375-hp 5.6-liter V-8 to tow around. That engine and the seven-speed automatic it pairs with, both new in 2017, made the van good for 15 mpg during our highway test. In regular driving, away from our 200-mile test loop, the Nissan averaged only 11 mpg during our two-week test. But you can’t beat the space in back.

2017 Ford F-250 Super Duty: 15 mpg

EPA highway estimate: Not rated

Model tested: 2017 Ford F-250 Super Duty V-8 SuperCab 4×4

Ford offers a wide variety of powertrain choices and cab configurations for its F-series pickups, particularly some genuinely miserly setups in the full-size F-150, including the base 3.3-liter V-6, the diesel variant, and the forthcoming Lightning EV. For Super Duty models, Ford sticks with V-8s; buyers can choose a 6.2-liter gasoline engine or a 6.7-liter diesel. The latter is more efficient, at least on our test loop, where diesel F-250 and F-350 models we tested notched 17 mpg and a 9140-pound diesel dually F-450 managed 16 mpg. Any of those would’ve qualified for this list if not for this lower-scoring four-wheel-drive Super Duty truck, which earned just 15 mpg from its 6.2-liter gas engine.

2020 Chevrolet Silverado 2500 HD: 14 mpg

EPA highway estimate: Not rated

Model tested: 2020 Chevrolet Silverado 2500 HD 6.6L V-8 4×4

Equipped with a 6.6-liter V-8 engine and a six-speed automatic transmission, the gas-burning Chevrolet Silverado 2500 averaged 14 mpg over 200 miles. The heavy-duty Silverados—there’s also a 3500—were redesigned for 2020. The engine tested here, which is new with this generation, makes 401 horsepower and 464 lb-ft of torque, a significant increase over the outgoing 6.0-liter V-8. If you have your heart set on a heavy-duty Silverado but fuel economy is important to you, consider the diesel version, which earned 19 mpg in our highway test.

2020 Ford F-350 Super Duty: 14 mpg

EPA highway estimate: Not rated

Model tested: 2020 Ford F-350 Tremor 7.3L 4×4

Rounding out the complement of Ford Super Duty trucks on this list, the F-350 ranks as one of the least efficient vehicles we’ve run around our loop in four years of testing. This particular F-350 had the factory bro-dozer Tremor package with meaty all-terrain tires and a lift kit. It was powered by pushrod gas engine that Ford calls Godzilla, a 7.3-liter V-8 making 430 horsepower and 475 lb-ft of torque that pairs with a 10-speed automatic transmission. New for 2020, the engine is the most powerful in the class. But with great power often comes lackluster fuel economy, and this is no exception.

2017 Ram 2500: 14 mpg

EPA highway estimate: Not rated

Model tested: 2017 Ram 2500HD 6.4L Gasoline V-8 Crew Cab 4×4

Like other heavy-duty trucks, the Ram 2500 is built for hauling capability. It can tow up to 17,980 pounds. The four-wheel-drive version we tested came with the 2500’s optional 410-hp 6.4-liter V-8 and a six-speed automatic. That configuration netted a thoroughly uninspiring 14 mpg on our test loop. On the upside, it can probably tow an entire gas station.

2021 Ram 1500 TRX: 13 mpg

EPA highway estimate: 14 mpg

Model tested: 2021 Ram 1500 TRX

It may feel more like an EV world every day, but Ram’s not ready to give up on raw, internally combusted power just yet. The 2021 Ram 1500 TRX has an absurd 702-hp supercharged 6.2-liter V-8, which it shares with Dodge’s Hellcat family. The truck weighs almost 7000 pounds. And at 3.7 seconds to 60 mph, it’s the fastest pickup we’ve ever tested. It also has the worst highway fuel economy of any vehicle that’s completed our 200-mile highway loop. At 13 mpg, you’d need 15 gallons of gas for a 200-mile jaunt at 75 mph. Luckily, the TRX has a 33-gallon tank.

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