GMC S15 Cab Chassis 2WD
14 MPG The 1988 GMC S15 Cab Chassis 2WD is EPA-rated at 14 MPG combined (14 city / 14.5 highway). Over 15,000 miles a year that is about 1071 gallons, $3429 a year in fuel, or $0.229 per mile at $3.20/gal.
Across its full 1984–1988 run it averages 14.1 MPG, essentially flat across 5 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 | $0.179 | $1786 | $2679 | $3571 |
| $3.00/gal | $0.214 | $2143 | $3214 | $4286 |
| $3.20/gal | $0.229 | $2286 | $3429 | $4571 |
| $3.50/gal | $0.250 | $2500 | $3750 | $5000 |
| $4.00/gal | $0.286 | $2857 | $4286 | $5714 |
| $4.50/gal | $0.321 | $3214 | $4821 | $6429 |
| $5.00/gal | $0.357 | $3571 | $5357 | $7143 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 1988 | 14 MPG | 14 | 14.5 | $4450 | 635 | 2 |
| 1987 | 14.3 MPG | 14 | 15 | $4417 | 630 | 3 |
| 1986 | 14.3 MPG | 14 | 15.3 | $4417 | 630 | 3 |
| 1985 | 14.3 MPG | 14 | 15 | $4425 | 631 | 4 |
| 1984 | 13.8 MPG | 13.5 | 14.5 | $4550 | 649 | 4 |
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 29 special purpose vehicle 2wd models tracked here, the GMC S15 Cab Chassis 2WD ranks 25 on current figures, against a class average of 18.9 MPG.
Closest more-efficient alternatives in the same class: Chevrolet Colorado Cab Chassis 2WD (15), GMC Canyon Cab Chassis 2WD (15), Cadillac Commercial Chassis (16), Chevrolet Silverado Cab Chassis 2WD (16), GMC Sierra Cab Chassis 2WD (16).
Tailpipe CO₂ is rated at 635 grams per mile, which works out to roughly 9.5 tonnes a year at 15,000 miles.
Questions
What MPG does the GMC S15 Cab Chassis 2WD get?
The 1988 GMC S15 Cab Chassis 2WD is rated at 14 MPG combined by the EPA — 14 city and 14.5 highway. Across all 5 model years in the database it averages 14.1 MPG, ranging from 13 to 17 depending on year and trim.
How much does a GMC S15 Cab Chassis 2WD cost in fuel per year?
At 14 MPG and 15,000 miles a year, it burns about 1071 gallons — roughly $3429 a year with fuel at $3.20 a gallon, or $0.229 per mile. The EPA's own published annual figure for the 1988 model is $4450.
Has the GMC S15 Cab Chassis 2WD become more efficient over time?
Barely. It sits at 14 MPG today against 13.8 in 1984 — essentially flat across 5 model years, with efficiency gains offset by weight and power creep.
Is the GMC S15 Cab Chassis 2WD efficient for its class?
It ranks 25 of 29 in the Special Purpose Vehicle 2WD class on current figures, against a class average of 18.9 MPG. That is 4.9 worse than typical for the class.
Compare with similar models
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.