23 MPG combined isn’t going to win any awards in 2018, and it didn’t when the Lexus IS 350 debuted either. Let’s be clear, no owner buys this car for its economy. They buy it for its refined V6 power, its sharp handling, and its Lexus badge. This particular buyer prioritizes a smooth, naturally aspirated engine over a fuel-sipping four-cylinder, and they are generally willing to pay the premium at the pump.

City and highway performance

The EPA estimates of 20 MPG in the city and 28 MPG on the highway accurately reflect the realities of driving the IS 350. The city figure suffers, as is typical, due to the engine’s larger displacement and the need to work harder in stop-and-go traffic. The eight-speed automatic transmission, while smooth and responsive, doesn’t completely mitigate the engine’s thirst when starting from a standstill. On the open road, the IS 350 fares better. The engine settles into a comfortable cruise, and the transmission makes good use of its higher gears to keep the RPMs down. However, spirited driving on twisty roads can quickly send that highway number plummeting, as the V6 likes to rev and reward the driver with its sonorous exhaust note. The IS MPG across all years shows there has not been significant improvement since this generation debuted.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2018 Lexus IS 350 is exactly $2,500. This figure is calculated based on driving 15,000 miles per year, with 55% of those miles driven in the city and 45% on the highway, and using the national average fuel price for premium unleaded gasoline. It’s important to remember that this is only an estimate, and your actual fuel costs may vary depending on your driving habits, local fuel prices, and the type of driving you do. For example, someone who primarily drives in stop-and-go city traffic will likely exceed this estimate, while someone who mainly cruises on the highway may come in under it.

Real-world expectations

While the EPA’s numbers provide a useful benchmark, IS 350 owners report slightly lower real-world fuel economy. Combined MPG figures in the low 20s are common, especially with a lead foot or frequent commutes in congested areas. Remember that the 3.5L V6 is not engineered for ultimate fuel sippage, it is meant to deliver a spirited driving experience with instant throttle response. The typical IS 350 buyer isn’t hypermiling, they’re enjoying the car’s performance. Therefore, consider the EPA numbers as optimistic, and factor in your own driving style when budgeting for fuel costs.

How it compares

Compared to its competitors, the 2018 Lexus IS 350’s fuel economy is squarely in the middle of the pack. The BMW 340i from that year, with its turbocharged inline-six, achieved an EPA-estimated 25 MPG combined. A Mercedes-Benz C43 AMG, also turbocharged and all-wheel drive, offered similar figures. Even the Infiniti Q50 with the twin-turbo 3.0L V6 often sees slightly better real-world economy than the IS 350. The Lexus offers a blend of luxury, reliability, and performance, but it sacrifices ultimate fuel efficiency to achieve it. For those seeking a truly frugal option, the four-cylinder versions of these competitors offer significantly improved MPG, but at the expense of power and driving enjoyment. Consider reviewing all Lexus fuel economy data to see how other Lexus models stack up.

Tips to maximize efficiency

Avoid aggressive acceleration and hard braking. The IS 350’s V6 is responsive, but every hard acceleration burns fuel. Try to anticipate traffic flow and maintain a steady speed, using the throttle smoothly and gradually. Maintaining momentum is key to improving fuel economy and also enhances the quiet experience expected from a Lexus.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, which reduces fuel economy. Check your tire pressure regularly, ideally weekly, and inflate them to the recommended pressure listed on the sticker inside the driver’s side door. Even a few PSI below the recommended pressure can have a noticeable impact on fuel consumption.

Reduce unnecessary weight in the vehicle. Carrying extra weight in your trunk or backseat puts additional strain on the engine, decreasing fuel efficiency. Remove any items you don’t need, such as sports equipment, tools, or bulky items. You would be surprised how much lighter your car can get when you empty everything out!

Use the cruise control on the highway. Cruise control helps maintain a constant speed, which can improve fuel economy compared to manually controlling the throttle. Use the cruise control on long, relatively flat stretches of highway, but be sure to disengage it when driving in hilly terrain or heavy traffic to maintain safe control of the vehicle.

Consider using a lighter weight motor oil. While the manufacturer’s recommended oil viscosity is important, using a high-quality synthetic oil specifically designed for fuel efficiency can sometimes provide a small but measurable improvement in MPG. Consult with a trusted mechanic before making any changes to your oil.