1999 Lexus GS 300/GS 400: MPG and fuel economy

This page collects every fuel-economy figure the EPA publishes for the 1999 Lexus GS 300/GS 400. Below you will find the headline combined, city, and highway MPG, the estimated annual fuel cost at three different driving levels, the tailpipe CO₂ emissions, and a full breakdown of the engine and drivetrain. The EPA rates 2 separate variants of this car (different engine, transmission, or drivetrain combinations), and you can compare them side by side in the trims table. If you want to know whether this generation got more or less efficient over the years, the year-over-year table further down covers every model year the EPA has rated.

Fuel economy at a glance

These are the EPA's official ratings for the 1999 Lexus GS 300/GS 400. The numbers come from a standardised laboratory test cycle and are the same figures that appear on the window sticker of every new car. Real-world mileage varies with driving style, weather, fuel quality, and how heavily loaded the car is.

When the EPA tests several variants of the same nameplate (for example, a front-wheel-drive version and an all-wheel-drive version), each gets its own rating. The figures shown here are the headline variant, taken as the configuration with the best combined MPG. The trims table further down covers all 2 variants side by side.

Combined MPG is a 55/45 weighted blend of the city and highway test cycles. The EPA uses it as the single number you can compare across the entire dataset, including hybrids and EVs (which use the equivalent MPGe figure).

How the 1999 Lexus GS 300/GS 400 compares

The 1999 Lexus GS 300/GS 400 returns 20 combined MPG. Cars in the Midsize Cars class for the same model year average 19.4 MPG, which puts this car ahead of the class average by about 3%.

The most efficient car in the Midsize Cars class for the 1999 model year is the Dodge Stratus at 27 MPG. The bar chart below puts the Lexus GS 300/GS 400 alongside the class best and the class average so you can see the full picture.

For broader context, the average new car of the 1999 model year (across all classes) returns 19.1 MPG. Larger vehicles pull the all-cars average down, so do not use that figure on its own to judge a small car or a hybrid. The full list of the most efficient cars of the 1999 model year is on its own page.

Trim variants rated for 1999

The EPA rates 2 separate variants of the 1999 Lexus GS 300/GS 400. The differences come from the engine size, transmission type, and drivetrain (front-wheel drive, all-wheel drive, and so on). The same nameplate can land several MPG apart depending on the configuration you actually buy.

Annual fuel cost across driving patterns

The headline annual fuel cost the EPA publishes assumes 15,000 miles of driving per year and a fuel mix of 55% city and 45% highway. The dollar figure is calculated using the EPA's current reference price for premium gasoline, which is $4.61/gallon. EPA updates that reference periodically rather than tracking live pump prices, so treat it as a window-sticker estimate rather than today's pump number.

The table below scales the EPA's number to three common driving patterns. The combined MPG and the reference fuel price stay constant, only the annual mileage changes. To get a current-prices estimate, take your local gas price and multiply by 750 gallons (the car's annual consumption at the rated MPG).

Year-over-year MPG for the Lexus GS 300/GS 400

The EPA has rated the Lexus GS 300/GS 400 across 3 model years, from 1998 Lexus GS 300/GS 400 through 2000 Lexus GS 300/GS 400. The numbers below are the best combined MPG figure the EPA published for each year, which lets you see when the car was at its most efficient and how recent generations stack up.

Combined MPG has stayed in roughly the same range across the run. The peak rating came with the 1999 Lexus GS 300/GS 400 at 20 MPG.

Compare against other Midsize Cars for 1999

If you are cross-shopping the 1999 Lexus GS 300/GS 400, the most useful comparison is against the other cars in the Midsize Cars class for the same model year. The list below shows the highest-MPG peers, ranked from most to least efficient. Click any of them to open its full page.

The Dodge Stratus leads this group at 27 MPG, 7 MPG ahead of the 1999 Lexus GS 300/GS 400.

Specifications

The 1999 Lexus GS 300/GS 400 runs a 3-liter 6-cylinder engine paired with a automatic 5-spd, sending power through rear-wheel drive.

Engine, transmission, and drivetrain together drive most of the variation in fuel economy across trims. A larger engine moves the car with less effort but burns more fuel. A turbo lets a small engine punch above its weight, often without much MPG penalty. All-wheel drive adds traction and weight, and usually costs a couple of MPG compared with two-wheel drive of the same engine.

Vehicle class

Midsize Cars

Engine

3L 6-cylinder

Transmission

Automatic 5-spd

Drivetrain

Rear-Wheel Drive

Fuel type

Premium

Annual petroleum use

14.9 barrels per year

Common questions about the 1999 Lexus GS 300/GS 400

Quick answers to the questions people most often search for when looking up the 1999 Lexus GS 300/GS 400.

• Is the 1999 Lexus GS 300/GS 400 fuel efficient?

  It is in line with the rest of the class. The 1999 Lexus GS 300/GS 400 returns 20 combined MPG, and the average car in the Midsize Cars class for the same model year sits at 19.4 MPG.
• What MPG does the 1999 Lexus GS 300/GS 400 get?

  The EPA rates the 1999 Lexus GS 300/GS 400 at 20 combined MPG, 18 MPG in city driving, and 23 MPG on the highway. Real-world numbers depend on your driving style, the weather, and how loaded the car is.
• How much does it cost to fuel a 1999 Lexus GS 300/GS 400 per year?

  The EPA estimates an annual fuel cost of $3,450 for the 1999 Lexus GS 300/GS 400. That figure assumes 15,000 miles of driving per year, a 55% city and 45% highway split, and the EPA's published average fuel price for the rated fuel grade.
• Does the 1999 Lexus GS 300/GS 400 require premium gas?

  Yes. The EPA lists the 1999 Lexus GS 300/GS 400 as requiring premium gasoline. Running it on regular can reduce performance and may affect engine warranties, so it is not a recommended way to save at the pump.
• Has the Lexus GS 300/GS 400 become more fuel efficient over time?

  Combined MPG has stayed close to flat across the run. Both the earliest (1998 Lexus GS 300/GS 400, 19 MPG) and most recent (2000 Lexus GS 300/GS 400, 19 MPG) versions sit in the same range.
• How much CO₂ does the 1999 Lexus GS 300/GS 400 emit?

  Tailpipe CO₂ emissions are 444 g/mi. Multiplied across a typical year of driving (15,000 miles) that works out to about 6,665 kilograms of CO₂.
• What is the difference between the city and highway MPG of the 1999 Lexus GS 300/GS 400?

  City driving returns 18 MPG and highway driving returns 23 MPG, a gap of 5 MPG. The two figures are close enough that the car will hold its rated efficiency well across most driving patterns.
• What engine is in the 1999 Lexus GS 300/GS 400?

  The 1999 Lexus GS 300/GS 400 has a 3-liter 6-cylinder engine.
• What transmission and drivetrain does the 1999 Lexus GS 300/GS 400 have?

  The 1999 Lexus GS 300/GS 400 comes with a automatic 5-spd transmission and rear-wheel drive.
• How does the 1999 Lexus GS 300/GS 400 compare to the best car in its class?

  The most efficient car in the Midsize Cars class for the 1999 model year is the Dodge Stratus at 27 combined MPG. The Lexus GS 300/GS 400 returns 20 MPG, a gap of 7 MPG. If you are comparing on fuel economy alone, the class leader is worth a look.

Source: U.S. EPA fuel economy dataset. Annual fuel cost figures assume 15,000 miles of driving per year and a 55% city, 45% highway split. Real-world mileage varies with driving conditions, vehicle maintenance, fuel quality, and driver behaviour.