Dodge Diplomat
14.3 MPG The 1989 Dodge Diplomat is EPA-rated at 14.3 MPG combined (13 city / 17 highway). Over 15,000 miles a year that is about 1049 gallons, $3357 a year in fuel, or $0.224 per mile at $3.20/gal.
Across its full 1984–1989 run it averages 14.5 MPG, essentially flat across 6 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 | $0.175 | $1748 | $2622 | $3497 |
| $3.00/gal | $0.210 | $2098 | $3147 | $4196 |
| $3.20/gal | $0.224 | $2238 | $3357 | $4476 |
| $3.50/gal | $0.245 | $2448 | $3671 | $4895 |
| $4.00/gal | $0.280 | $2797 | $4196 | $5594 |
| $4.50/gal | $0.315 | $3147 | $4720 | $6294 |
| $5.00/gal | $0.350 | $3497 | $5245 | $6993 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 1989 | 14.3 MPG | 13 | 17 | $5483 | 633 | 3 |
| 1988 | 15 MPG | 13.7 | 17.7 | $5283 | 609 | 3 |
| 1987 | 14.3 MPG | 13 | 16.7 | $4733 | 633 | 3 |
| 1986 | 14.3 MPG | 13.3 | 16.7 | $4717 | 629 | 3 |
| 1985 | 15 MPG | 13.7 | 17.7 | $5250 | 606 | 3 |
| 1984 | 14.3 MPG | 13.3 | 17 | $4367 | 623 | 3 |
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 Dodge Diplomat ranks 252 on current figures, against a class average of 27.3 MPG.
Closest more-efficient alternatives in the same class: Audi V8 (15), Mercedes-Benz 420SEL (15), Audi RS 7 (16), Cadillac CTS-V (16), Dodge Challenger SRT (16).
Tailpipe CO₂ is rated at 633 grams per mile, which works out to roughly 9.5 tonnes a year at 15,000 miles.
Questions
What MPG does the Dodge Diplomat get?
The 1989 Dodge Diplomat is rated at 14.3 MPG combined by the EPA — 13 city and 17 highway. Across all 6 model years in the database it averages 14.5 MPG, ranging from 12 to 18 depending on year and trim.
How much does a Dodge Diplomat cost in fuel per year?
At 14.3 MPG and 15,000 miles a year, it burns about 1049 gallons — roughly $3357 a year with fuel at $3.20 a gallon, or $0.224 per mile. The EPA's own published annual figure for the 1989 model is $5483.
Has the Dodge Diplomat become more efficient over time?
Barely. It sits at 14.3 MPG today against 14.3 in 1984 — essentially flat across 6 model years, with efficiency gains offset by weight and power creep.
Is the Dodge Diplomat efficient for its class?
It ranks 252 of 261 in the Midsize Cars class on current figures, against a class average of 27.3 MPG. That is 13.0 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.