The 2018 Lexus GS 350, with its 3.5L V6, achieves a combined fuel economy rating of 23 MPG. While not class-leading, this figure reflects a choice made by drivers who prioritize smooth power delivery, refined handling, and signature Lexus reliability over getting the most miles from each gallon. This is a car bought by professionals, empty-nesters, and those who appreciate a comfortable, understated luxury sedan that will start every time, deliver consistent performance, and hold its value.

City and highway performance

The EPA estimates the 2018 GS 350 will achieve 20 MPG in city driving and 28 MPG on the highway. The difference between these numbers shows the engine’s character. In urban environments, stop-and-go traffic keeps the GS 350 in the lower gears of its smooth eight-speed automatic transmission, impacting efficiency. However, on the open road, that transmission allows the engine to settle into a comfortable cruise, maximizing fuel economy and providing a relaxed driving experience. The 28 MPG highway figure is respectable for a naturally aspirated V6 of this size and power.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2018 Lexus GS 350 is $2,500. This figure is calculated based on driving 15,000 miles per year, with a mix of city and highway driving, and using the national average fuel price at the time of calculation. It’s a useful benchmark, but individual costs will vary depending on driving habits, local fuel prices, and the proportion of city versus highway miles driven. If you live in an area with significantly higher gas prices, or if your commute is primarily in stop-and-go traffic, expect to exceed this $2,500 estimate.

Real-world expectations

While the EPA provides a standardized baseline, your real-world MPG in the GS 350 will depend on several factors. Aggressive acceleration, frequent hard braking, and neglecting routine maintenance can all negatively impact fuel economy. Conversely, practicing smooth driving techniques, keeping your tires properly inflated, and adhering to the recommended maintenance schedule will help you achieve numbers closer to, or even slightly exceeding, the EPA estimates. Owners often average around 25 MPG in combined driving, indicating that the official figures are achievable with effort.

How it compares

The GS 350 sits in a competitive segment, and its fuel economy performance should be viewed in that context. The BMW 540i, with its turbocharged inline-six, achieves a slightly better 24 MPG combined. The Mercedes-Benz E450, another turbocharged six-cylinder competitor, also lands at 24 MPG combined. The Acura TLX, with its V6 engine achieves 24 MPG combined. Fuel economy is arguably not a key purchase factor for buyers in the luxury segment. Buyers concerned about optimization can review all Lexus fuel economy data. Lexus also offered hybrid versions of the GS, allowing a look at GS MPG across all years and powertrains.

Tips to maximize efficiency

Take advantage of the GS 350’s “ECO” driving mode. While it won’t transform the car into a Prius, it does alter throttle mapping and transmission shift points to prioritize fuel efficiency. The impact may be minor with aggressive driving, but consistently using ECO mode during daily commutes can yield savings over time.

Ensure your GS 350’s tires are properly inflated to the recommended pressure, which can be found on a sticker inside the driver’s side doorjamb. Under-inflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel.

Minimize idling. Modern engines are surprisingly efficient when running, but idling burns fuel unnecessarily. If you anticipate being stopped for more than a minute or two, it’s generally more fuel-efficient to turn off the engine and restart it.

Use cruise control on the highway whenever possible. Maintaining a consistent speed helps the GS 350 achieve optimal fuel economy. Avoid rapid acceleration and deceleration; anticipate traffic flow and adjust your speed smoothly.

Keep up with routine maintenance. Regular oil changes, air filter replacements, and spark plug maintenance can all contribute to improved fuel efficiency. A well-maintained engine runs more smoothly and efficiently, reducing fuel consumption.