20 MPG combined isn’t going to win any hypermiling contests, but that’s what you get driving a 2018 Kia K900 with the 3.8L V6. This isn’t a car for those chasing maximum efficiency; it’s a full-size luxury sedan designed for comfortable cruising and a quiet, composed ride. K900 buyers prioritize space, features, and a smooth driving experience over squeezing every last mile from a gallon of gasoline.

City and highway performance

The EPA estimates for the 2018 Kia K900 3.8L are 17 MPG in the city and 25 MPG on the highway. The city figure reflects the K900’s weight and the fuel required to repeatedly accelerate its mass from a standstill. The highway number is more respectable, thanks to the smooth-shifting 8-speed automatic transmission and relatively relaxed engine speeds at cruising velocity. The transmission helps make the most of the V6’s power, but physics ultimately dictates the sedan’s fuel consumption.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Kia K900 3.8L at $2,200. This figure is calculated based on driving 15,000 miles per year, with 45% of those miles driven in the city and 55% on the highway, using national average fuel prices at the time of calculation. Remember that actual fuel costs will vary based on individual driving habits, local fuel prices, and the specific blend of gasoline used.

Real-world expectations

While EPA numbers provide a standardized benchmark, real-world MPG for the 2018 K900 3.8L can change. Drivers who spend a lot of time in stop-and-go traffic will likely see figures closer to, or even below, the 17 MPG city estimate. Those who primarily drive on the open highway, maintaining consistent speeds, might achieve slightly better than the 25 MPG highway rating. Aggressive driving habits, frequent hard acceleration and braking, will negatively impact fuel economy. Owners who drive smoothly and perform regular maintenance are more likely to achieve numbers closer to the EPA estimates. See K900 MPG across all years for more.

How it compares

The 2018 Kia K900 3.8L’s fuel economy is generally in line with its competitors’ base models in the full-size luxury sedan segment. The Lexus LS 500’s EPA ratings are 19 MPG city and 30 MPG highway, giving it a slight edge on the highway. A BMW 740i rates at 21 MPG combined, a small improvement that might sway some buyers. The Cadillac CT6 with its 3.6L V6 achieves around 21 MPG combined as well. The K900 buyer is likely weighing factors beyond fuel efficiency, such as value, standard features, and Kia’s strong warranty. These other vehicles offer more engaging driving experiences that some buyers will see as a worthwhile tradeoff to the small difference in MPG. You can also see all Kia fuel economy data here.

Tips to maximize efficiency

Maintain a steady speed and avoid aggressive acceleration. The K900’s 3.8L V6 responds well to gradual throttle inputs. Anticipate traffic flow and avoid unnecessary braking, allowing the car to coast when possible. The K900’s weight means that momentum helps when maximizing fuel economy.

Make sure your tires are properly inflated to the recommended pressure listed on the driver’s side doorjamb. Underinflated tires increase rolling resistance, which reduces fuel efficiency. Check tire pressure regularly, especially with changes in temperature.

Keep up with routine maintenance, including oil changes and air filter replacements. A clean air filter ensures optimal airflow to the engine and fresh oil reduces friction which improves overall engine efficiency. These small maintenance items can collectively make a noticeable difference in fuel consumption.

Limit the use of accessories that put extra strain on the engine, such as air conditioning. The K900’s climate control is excellent at maintaining a comfortable cabin, but running it at full blast constantly will impact fuel economy. Use recirculated air when appropriate to reduce the cooling load.

Remove unnecessary weight from the vehicle. Extra cargo adds to the K900’s already substantial mass, requiring more energy to accelerate and maintain speed. Clearing out items you don’t need can incrementally improve fuel economy over time.