The Jeep J-20 does 11 mpg combined (10 city, 12 highway), which works out to about $3,491 a year in fuel at $3.20 a gallon and 12,000 miles. Against other V8 cars it sits below the average of 16.1 mpg.
Every Jeep J-20 engine, compared
The Jeep J-20 was rated in a single specification, so its gas mileage does not vary by version — only by model year. Yearly cost assumes 12,000 miles at $3.20 a gallon.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 5.9L 8-cyl | 10 / 12 | 1985–1988 | $3,491 |
What that actually costs
The Jeep J-20 burns a gallon every 11 miles, so 12,000 miles takes about 1091 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.291 |
| Fuel per year | $3,491 |
| Fuel over five years | $17,455 |
| Against other V8 cars | +$1,106 a year |
| EPA's own estimate | $5,650 a year |
City or highway — who is this car for
The Jeep J-20 gives up 2 mpg the moment you leave the motorway — 12 out there against 10 in town, a 20% drop worth $640 a year. A wide gap punishes stop-and-start traffic; a narrow one means the car doesn't care where you drive it.
| Measure | Value | Reading |
|---|---|---|
| City | 10 mpg | $3,840 a year if you only drive in town |
| Highway | 12 mpg | $3,200 a year if you mostly commute |
| Gap | +2 mpg (20%) | Typical for its type |
How the J-20 changed over the years
Combined figure across the 4 model years the J-20 was rated in, all of them at 11 mpg. Jumps usually mark a new generation or a new engine; dips often mean a heavier body or added all-wheel drive.
| Model year | Combined | City / Highway | Engines offered | Fuel per year |
|---|---|---|---|---|
| 1988 | 10 / 12 | 1 | $3,491 | |
| 1987 | 10 / 12 | 1 | $3,491 | |
| 1986 | 10 / 12 | 1 | $3,491 | |
| 1985 | 10 / 12 | 1 | $3,491 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 4 EPA ratings of the Jeep J-20 — 1 engine across 1985–1988. The mileage is EPA's laboratory figure, unchanged; the yearly bill is ours, at 12,000 miles and $3.20 a gallon, against EPA's own estimate of $5,650. Full method.
Frequently asked questions
What mpg does the Jeep J-20 get?
11 mpg combined on average — 10 in the city and 12 on the highway, per EPA ratings across 1985–1988.
How much does a Jeep J-20 cost in fuel per year?
About $3,491 at 12,000 miles and $3.20 a gallon — roughly $17,455 over five years, or 0.291 dollars a mile.
Which J-20 engine is the most economical?
The 5.9L 8-cyl at 11 mpg.
Is the J-20 good on fuel compared with similar cars?
Against other V8 cars it sits below the average of 16.1 mpg, computed across 3323 ratings.
Are these real-world J-20 figures?
No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the Jeep J-20 is $5,650 against the $3,491 we compute at 12,000 miles. Expect a little worse in practice: the spread between the city and highway figures is smaller than the spread between two drivers of the same one.
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