23 MPG combined isn’t going to win any hypermiling awards, but for the 2015 Mercedes-Benz E400 4matic Coupe, it’s a trade-off most owners are willing to make. This isn’t a car bought for frugality. It’s a stylish, all-weather capable coupe with a potent engine and a luxury badge. The E400 coupe buyer wants performance and panache and accepts the fuel consumption as a necessary, if not insignificant, expense.

City and highway performance

The EPA estimates 20 MPG in the city and 28 MPG on the highway for the 2015 E400 4matic Coupe. These figures reflect the demands of stop-and-go urban driving and the more consistent speeds of highway cruising. The 3.0L V6, while turbocharged for power, is still a relatively large engine, requiring more fuel during acceleration and idling. The 7-speed automatic transmission, while smooth and responsive, isn’t the most modern gearbox available, and newer 8- or 9-speed units often contribute to better economy, especially on the highway. The 4matic all-wheel-drive system also adds weight and internal friction, impacting fuel efficiency, but providing superior traction in inclement weather.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2015 Mercedes-Benz E400 4matic Coupe is $2,500. This figure is based on driving 15,000 miles per year, with a specific percentage dedicated to city versus highway driving, and using the EPA’s projection of national average fuel prices. While your actual fuel costs will vary depending on your driving habits and local fuel prices, this $2,500 figure provides a standardized baseline for comparison. It highlights the financial commitment involved in owning a luxury coupe with sporting aspirations and should be factored into the overall cost of ownership if you are seriously considering an E400.

Real-world expectations

While the EPA figures provide a useful benchmark, real-world fuel economy for the E400 4matic Coupe can vary significantly. Aggressive driving, frequent short trips, and heavy traffic will all negatively impact your MPG. Conversely, gentle acceleration, consistent highway speeds, and diligent maintenance can help you achieve figures closer to, or even slightly exceeding, the EPA estimates. Many owners report highway MPG numbers in the low 30s during long road trips.

It’s crucial to understand your own driving style and typical routes to set realistic expectations.

How it compares

Compared to other similar vehicles of the era, the 2015 E400’s fuel economy is fairly typical, though not class-leading. For example, the 2015 BMW 435i xDrive Coupe, with its 3.0L turbocharged inline-six and all-wheel drive, is rated at 22 MPG combined, 22 MPG city, and 32 MPG highway, slightly better on the highway but worse in the city, making it quite similar overall.

The Audi S5 Coupe from the same year, boasting a supercharged V6 and quattro all-wheel drive, achieves a combined 18 MPG, city 17 MPG, and highway 26 MPG, making it measurably less fuel efficient. These comparisons matter because the potential E400 buyer is likely cross-shopping these vehicles. The Mercedes offers a blend of luxury and all-weather performance, and E400 MPG across all years often falls within an acceptable range for those who prioritize those factors.

Tips to Maximize Efficiency

Take advantage of the E400’s Eco mode. This setting remaps the throttle response and shift points for optimal fuel efficiency. While you might sacrifice some of the car’s eagerness, you’ll see a noticeable improvement in MPG, especially in city driving. Consider using Eco mode for your daily commute and reserve Sport mode for spirited weekend drives.

Monitor your tire pressure regularly. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. The recommended tire pressure is listed on a sticker inside the driver’s side doorjamb. A small investment in a good tire pressure gauge is well worth it.

Minimize idling. Modern engines, including the E400’s V6, consume more fuel when idling than most people realize. If you’re stopped for more than a minute, such as at a long traffic light or waiting in a pickup line, it’s more efficient to turn off the engine. Restarting the engine consumes a negligible amount of fuel compared to prolonged idling.

Avoid aggressive acceleration and hard braking. Smooth, consistent driving is the key to maximizing fuel economy. Anticipate traffic flow and maintain a steady speed whenever possible. Rapid acceleration and abrupt braking not only waste fuel but also increase wear and tear on your vehicle. The E400 is quick, but driving it like a sports car will significantly hurt your MPG.

Keep up with scheduled maintenance. A well-maintained engine is a more efficient engine. Regular oil changes, air filter replacements, and spark plug maintenance ensure that your E400 is running optimally. Follow the manufacturer’s recommended maintenance schedule to keep your car in top condition and maximize fuel efficiency. You can find all Mercedes Benz fuel economy data if you are interested in viewing more Mercedes Benz vehicles.