The Isuzu I-Mark does 31.8 mpg combined (29.8 city, 35.5 highway), which works out to about $1,208 a year in fuel at $3.20 a gallon and 12,000 miles. Engine choice matters more than you'd think: 1.5L 4-cyl does 33.3 mpg while 1.8L 4-cyl does 29 — a difference of $171 a year. Against other 4-cyl cars it sits above the average of 25.7 mpg.
Every Isuzu I-Mark engine, compared
Gas mileage on the Isuzu I-Mark ranges from 33.3 down to 29 depending on which engine sits under the bonnet — a spread of $171 a year across 2 versions of the same car. Picking the right one often saves more fuel than picking a different car altogether. Yearly cost assumes 12,000 miles at $3.20 a gallon.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 1.5L 4-cyl | 31.3 / 37.3 | 1986–1989 | $1,153 | |
| 1.8L 4-cyl | 27 / 32 | 1984–1985 | $1,324 |
What that actually costs
The Isuzu I-Mark burns a gallon every 31.8 miles, so 12,000 miles takes about 377 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.101 |
| Fuel per year | $1,208 |
| Fuel over five years | $6,040 |
| Against other 4-cyl cars | −$286 a year |
| EPA's own estimate | $2,083 a year |
City or highway — who is this car for
The Isuzu I-Mark gives up 5.7 mpg the moment you leave the motorway — 35.5 out there against 29.8 in town, a 19% drop worth $207 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 | 29.8 mpg | $1,289 a year if you only drive in town |
| Highway | 35.5 mpg | $1,082 a year if you mostly commute |
| Gap | +5.7 mpg (19%) | Typical for its type |
How the I-Mark changed over the years
The I-Mark peaked in 1984 at 35 mpg (33 city, 38 highway) and was at its thirstiest in 1985 at 23 — 12 mpg apart, or $573 a year in fuel between buying one year and the other. The 1989 car does 33. 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 |
|---|---|---|---|---|
| 1989 | 31 / 37 | 1 | $1,164 | |
| 1988 | 31 / 37 | 1 | $1,164 | |
| 1987 | 31 / 37 | 1 | $1,164 | |
| 1986 | 32 / 38 | 1 | $1,129 | |
| 1985 | 21 / 26 | 1 | $1,670 | |
| 1984 | 33 / 38 | 1 | $1,097 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 6 EPA ratings of the Isuzu I-Mark — 2 engines across 1984–1989. 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 $2,083. Full method.
Frequently asked questions
What mpg does the Isuzu I-Mark get?
31.8 mpg combined on average — 29.8 in the city and 35.5 on the highway, per EPA ratings across 1984–1989.
How much does a Isuzu I-Mark cost in fuel per year?
About $1,208 at 12,000 miles and $3.20 a gallon — roughly $6,040 over five years, or 0.101 dollars a mile.
Which I-Mark engine is the most economical?
The 1.5L 4-cyl at 33.3 mpg, against 29 for the 1.8L 4-cyl — a difference of about $171 a year.
Is the I-Mark good on fuel compared with similar cars?
Against other 4-cyl cars it sits above the average of 25.7 mpg, computed across 4765 ratings.
Are these real-world I-Mark figures?
No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the Isuzu I-Mark is $2,083 against the $1,208 we compute at 12,000 miles. Expect a little worse in practice: the spread between the 35 and 23 mpg versions of this car is smaller than the spread between two drivers of the same one.
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