2004 Mitsubishi Diamante SedanFuel Economy & MPG Ratings

Gasoline Midsize CarsFront-Wheel Drive

Photo: IFCAR. Public domain. via Wikimedia Commons

City

MPG

Highway

MPG

Combined

MPG

Trim Comparison

Automatic 4-spd

Premium

City

Hwy

Comb

Fuel cost: $4,550/yr

Automatic (S4)

Premium

City

Hwy

Comb

Fuel cost: $4,550/yr

Trim	Engine	City	Hwy	Combined	Fuel Cost/yr
Automatic 4-spd	Premium	15	23	18	$4,550
Automatic (S4)	Premium	15	23	18	$4,550

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: 3.5L 6-cyl
Transmission: 4-speed Automatic
Drivetrain: FWD
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: 3.5L, 6-cylinder
Induction Type: SOHC
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

State	Gas Price	Annual Cost	vs. National Avg
National AvgEPA default	$4.490/gal	$3,742/yr	—
California	$5.957/gal	$4,964/yrHIGHEST	+$1,222
Texas	$3.888/gal	$3,240/yrLOWEST	$-502
Florida	$4.136/gal	$3,447/yr	$-295
New York	$4.522/gal	$3,768/yr	+$26
Ohio	$4.510/gal	$3,758/yr	+$16
Washington	$5.591/gal	$4,659/yr	+$917
Colorado	$4.618/gal	$3,848/yr	+$106
Minnesota	$4.344/gal	$3,620/yr	$-122
Massachusetts	$4.448/gal	$3,707/yr	$-35