The 2015 Lexus GS 350, with its 3.5L V6, gets a combined EPA fuel economy rating of 23 MPG. This figure reflects the car’s goal: a refined driving experience without using too much gas. It’s not a Prius. It’s a luxury sedan that balances performance, comfort, and style, and buyers generally understand this tradeoff.

City and highway performance

The EPA estimates the GS 350 gets 19 MPG in the city and 29 MPG on the highway. The lower city figure is because the engine works harder in stop-and-go traffic. It also reflects that the naturally aspirated V6 is designed for smooth power delivery across the rev range, rather than just low-end torque. The 29 MPG highway rating is better, showing the effectiveness of the 8-speed automatic transmission in keeping the engine at optimal RPMs for cruising. Frequent long-distance road trips will mean fewer stops at the gas station. The GS 350 wasn’t designed primarily for city driving. Its highway fuel economy supports this.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Lexus GS 350 at $2,500. This is based on driving 15,000 miles per year and using then-current national average fuel prices. This is an estimate. Actual fuel costs will change based on driving habits, location, and gas prices. Aggressive driving will increase that number. Consider this $2,500 figure when weighing running costs. It puts the GS 350 in competition with BMW and Mercedes, but GS 350 prospects should consider their typical driving.

Real-world expectations

EPA ratings are a standardized baseline, but real-world fuel economy often differs. Owners of the 2015 GS 350 should expect numbers close to the EPA estimates, but maybe a little lower, depending on their driving. Driving aggressively will negatively impact fuel consumption. Maximizing highway cruising and following speed limits could get results closer to 29 MPG. Keep up with the maintenance schedule (especially spark plug replacement) for best economy. Tire pressure is also important. See GS MPG across all years for longer-term trends.

How it compares

In the mid-size luxury sedan segment, the 2015 Lexus GS 350 had strong competition. The BMW 535i, with its turbocharged six-cylinder engine, was rated at 20 MPG city and 30 MPG highway, a slightly better highway number. The Mercedes-Benz E350 achieved 21 MPG city and 31 MPG highway with its V6. These numbers are important to buyers comparing vehicles. The Lexus is a little behind these options, but the GS 350 has above-average reliability. The Audi A6 3.0T, with its supercharged V6, gets roughly the same MPG, but costs more. Acura TLX V6 versions perform closer to 21MPG combined. Buyers are willing to accept the GS 350’s fuel economy because it’s not far off from its direct competitors.

Tips to maximize efficiency

Watch traffic flow and avoid hard acceleration and braking. The GS 350’s V6 responds well to smooth inputs. On the highway, cruise control helps maintain speed and reduces fuel use, and improves passenger comfort.

Keep your tires inflated to the recommended pressure. The correct pressure is on a sticker inside the driver’s side doorjamb or in the owner’s manual. Underinflated tires increase rolling resistance and reduce fuel economy by a little.

Reduce idling. Idling wastes fuel because the engine burns gas without moving. If you’re waiting for more than a few seconds, turn off the engine and restart it, which is more fuel-efficient; this applies to cars with conventional automatic transmissions, not hybrids.

Consider using the GS 350’s “Eco” drive mode when performance isn’t critical. This mode changes the throttle response and transmission shift points to prioritize fuel efficiency, affecting acceleration a little, and helps get the best results for commutes. See all Lexus fuel economy data to see how the full model range performs.