Mitsubishi Diamante
18 MPG The 2002 Mitsubishi Diamante is EPA-rated at 18 MPG combined (16 city / 23 highway). Over 15,000 miles a year that is about 833 gallons, $2667 a year in fuel, or $0.178 per mile at $3.20/gal.
Across its full 1992–2002 run it averages 18.3 MPG, essentially flat across 11 model years.
Running cost at different fuel prices and mileages
The figure everyone actually wants, and the one the EPA does not publish — because it depends on a fuel price no agency will commit to.
| Fuel price | Per mile | 10,000 mi/yr | 15,000 mi/yr | 20,000 mi/yr |
|---|---|---|---|---|
| $2.50/gal | $0.139 | $1389 | $2083 | $2778 |
| $3.00/gal | $0.167 | $1667 | $2500 | $3333 |
| $3.20/gal | $0.178 | $1778 | $2667 | $3556 |
| $3.50/gal | $0.194 | $1944 | $2917 | $3889 |
| $4.00/gal | $0.222 | $2222 | $3333 | $4444 |
| $4.50/gal | $0.250 | $2500 | $3750 | $5000 |
| $5.00/gal | $0.278 | $2778 | $4167 | $5556 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 2002 | 18 MPG | 16 | 23 | $4300 | 494 | 1 |
| 2001 | 18 MPG | 16 | 23 | $4300 | 494 | 1 |
| 2000 | 18 MPG | 16 | 23 | $4300 | 494 | 1 |
| 1999 | 18 MPG | 16 | 22 | $4300 | 494 | 1 |
| 1998 | 18 MPG | 16 | 23 | $4300 | 494 | 1 |
| 1997 | 19 MPG | 16 | 24 | $4050 | 468 | 1 |
| 1996 | 18.5 MPG | 16 | 22.5 | $4175 | 481 | 2 |
| 1995 | 19 MPG | 16 | 23 | $4050 | 468 | 2 |
| 1994 | 18 MPG | 16 | 22 | $4300 | 494 | 2 |
| 1993 | 18 MPG | 16 | 22.5 | $4300 | 494 | 2 |
| 1992 | 18.5 MPG | 16 | 22.5 | $4175 | 481 | 2 |
Where a model year offered several engines or drivetrains, the figure is the average across all EPA-tested trims that year — the trim count is shown so you can see how much averaging is involved.
How it compares in its class
Among the 261 midsize cars models tracked here, the Mitsubishi Diamante ranks 222 on current figures, against a class average of 27.3 MPG.
Closest more-efficient alternatives in the same class: Audi 100 (18.5), Bentley Flying Spur (19), BMW 550i xDrive (19), BMW M850i xDrive Gran Coupe (19), Buick Riviera (19).
Tailpipe CO₂ is rated at 494 grams per mile, which works out to roughly 7.4 tonnes a year at 15,000 miles.
Questions
What MPG does the Mitsubishi Diamante get?
The 2002 Mitsubishi Diamante is rated at 18 MPG combined by the EPA — 16 city and 23 highway. Across all 11 model years in the database it averages 18.3 MPG, ranging from 18 to 19 depending on year and trim.
How much does a Mitsubishi Diamante cost in fuel per year?
At 18 MPG and 15,000 miles a year, it burns about 833 gallons — roughly $2667 a year with fuel at $3.20 a gallon, or $0.178 per mile. The EPA's own published annual figure for the 2002 model is $4300.
Has the Mitsubishi Diamante become more efficient over time?
Barely. It sits at 18 MPG today against 18.5 in 1992 — essentially flat across 11 model years, with efficiency gains offset by weight and power creep.
Is the Mitsubishi Diamante efficient for its class?
It ranks 222 of 261 in the Midsize Cars class on current figures, against a class average of 27.3 MPG. That is 9.3 worse than typical for the class.
EPA test figures from fueleconomy.gov. Cost per mile and annual fuel spend are computed at a reference price of $3.20 per gallon — use your own price. Estimates based on official test figures and average fuel prices. Real-world consumption varies with driving style, load, terrain and maintenance.