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How many miles per gallon does a 1999 Lexus gs400 get?

The 1999 Lexus GS400 typically gets about 17–18 mpg in city driving and about 25–26 mpg on the highway, for a combined around 21–22 mpg.


This article examines the official EPA estimates from the era, real-world performance, and the factors that influence fuel economy in this late-1990s luxury sedan powered by a 4.0-liter V8.


EPA figures for the 1999 GS400


Below are the typical EPA estimates for the 1999 GS400. Real-world mileage can vary based on condition, maintenance, and driving style.



  • City MPG: 17–18 mpg

  • Highway MPG: 25–26 mpg

  • Combined MPG: about 21–22 mpg


These figures reflect the EPA test cycle used at the time and provide a baseline for comparing with other vehicles. Actual mileage in everyday driving often falls outside these ranges depending on conditions.


What affects the GS400’s fuel economy?


Driving style and conditions


Aggressive acceleration, frequent stops, heavy traffic, and idling can lower mpg. Conversely, steady speeds on highways and gentle accelerations help approach the highway figures.


Vehicle maintenance and condition


Regular maintenance—proper oil changes, air filter replacement, tire pressure, and alignment—plays a critical role in preserving fuel economy on this older 4.0L V8. Worn spark plugs or sensors can increase fuel consumption.


Vehicle specifics


The GS400 uses a 4.0-liter 1UZ-FE V8 and a luxury-weighted platform. Transmission type (automatic) and drivetrain (rear-wheel drive) influence efficiency. Heavier options or aftermarket modifications can reduce mpg.


Ways to maximize fuel economy


Even with a performance-oriented luxury sedan, some straightforward steps can help improve mpg over time. Consider the following:



  • Keep tires inflated to the recommended pressure and ensure proper alignment.

  • Perform regular maintenance and replace air filters as needed.

  • Drive at steady speeds and minimize abrupt accelerations.

  • Remove excess weight from the car and avoid roof racks when not in use.

  • Use the appropriate grade of premium fuel as recommended by Lexus.


By following routine maintenance and mindful driving, owners may see mileage closer to the higher end of the EPA range under favorable conditions.


Summary


The 1999 Lexus GS400 delivers roughly 17–18 mpg in city driving and 25–26 mpg on the highway, translating to a combined around 21–22 mpg. Real-world mileage varies with driving style, maintenance, and overall vehicle condition. For a classic luxury four-door with a V8, these figures align with era expectations, and attentive upkeep can help preserve efficiency over time.

Is the GS400 expensive to maintain?


The estimated cost to maintain and repair a Lexus GS400 ranges from $105 to $3513, with an average of $440.



How long will a 1999 Lexus LS400 last?


With proper maintenance, the LS400 will go 400,000 miles without a problem.



How much is a 1999 Lexus GS300 worth?


The value of a used 1999 Lexus GS 300 ranges from $892 to $2,472, based on vehicle condition, mileage, and options.



How many miles per gallon does a GS400 get?


Fuel Economy

City16 mpg
Highway22 mpg
Combined18 mpg


Kevin's Auto

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.