2003 Infiniti M45Fuel Economy & MPG Ratings

Gasoline Compact CarsRear-Wheel Drive
2003 Infiniti M45

Photo: IFCAR. Public domain. via Wikimedia Commons

City
16
MPG
Highway
22
MPG
Combined
18
MPG

Real-World MPG

Based on 2 owner reports via EPA fueleconomy.gov

19.3MPG average+7.5% vs EPA label
EPA combined: 18 MPG · Owner reported avg: 19.3 MPG

Range: 18–21 MPG

Driving mix: City 55% / Highway 45%

Source: EPA fueleconomy.gov “Your MPG” owner submissions. Real-world results vary by driver behavior, conditions, and equipment.

Owner reported MPG for this vehicle averages 19.3 real world MPG based on 2 owner reports. EPA combined rating is 18 MPG.

Trim Comparison

Automatic (S5)
Premium
City
16
Hwy
22
Comb
18
Fuel cost: $4,550/yr
Annual Fuel Cost
$4,550

Based on gasoline at $3.67/gal, 15,000 miles/year

5-Year Fuel Savings
$-10,750

vs. average new vehicle

EPA Fuel Economy Score: -1/10
GHG Score: -1/10

Environment

CO₂ Tailpipe Emissions
494 g/mile
Annual Petroleum Consumption
16.5 barrels

Specifications

Engine
4.5L 8-cyl
Transmission
5-speed Automatic
Drivetrain
RWD
Body Style
Sedan
GVWR
Class 1 (≤6,000 lbs)

Source: EPA fuel economy data & NHTSA vPIC. Specifications reflect the most common trim configuration.

Engine & Efficiency Details

Source: EPA fueleconomy.gov

Engine Size
4.5L, 8-cylinder
Fuel Type
Premium Gasoline

Annual Fuel Cost by State

Prices as of week ending May 18, 2026 · Source: EIA

National AvgEPA default
$4.490/gal$3,742/yr
California
$5.957/gal$4,964/yr
Texas
$3.888/gal$3,240/yr
Florida
$4.136/gal$3,447/yr
New York
$4.522/gal$3,768/yr
Ohio
$4.510/gal$3,758/yr
Washington
$5.591/gal$4,659/yr
Colorado
$4.618/gal$3,848/yr
Minnesota
$4.344/gal$3,620/yr
Massachusetts
$4.448/gal$3,707/yr

Calculated at 15,000 miles/year (EPA standard assumption) using 18 MPG combined. Regular gasoline prices. Actual costs vary.

Related

Infiniti M45 MPG History
See how this model's fuel economy changed by year

Similar Compact Cars, 2003

All Infiniti Models