1990 GMC C2500 Sierra
11 configurations — EPA fuel economy ratings
| Trim / Variant | City MPG | Hwy MPG | Combined MPG | Fuel | Drive | Engine | Transmission |
|---|---|---|---|---|---|---|---|
| C2500 Sierra 2WD | 15 | 16 | 15 | Regular Gasoline | Rear-Wheel Drive | 4.3L 6-cyl | Automatic 3-spd |
| C2500 Sierra 2WD | 14 | 17 | 15 | Regular Gasoline | Rear-Wheel Drive | 4.3L 6-cyl | Manual 4-spd |
| C2500 Sierra 2WD | 15 | 22 | 18 | Regular Gasoline | Rear-Wheel Drive | 4.3L 6-cyl | Manual 5-spd |
| C2500 Sierra 2WD | 13 | 14 | 13 | Regular Gasoline | Rear-Wheel Drive | 5L 8-cyl | Automatic 3-spd |
| C2500 Sierra 2WD | 14 | 17 | 15 | Regular Gasoline | Rear-Wheel Drive | 5L 8-cyl | Automatic 4-spd |
| C2500 Sierra 2WD | 14 | 18 | 15 | Regular Gasoline | Rear-Wheel Drive | 5L 8-cyl | Manual 5-spd |
| C2500 Sierra 2WD | 12 | 16 | 13 | Regular Gasoline | Rear-Wheel Drive | 5.7L 8-cyl | Automatic 4-spd |
| C2500 Sierra 2WD | 11 | 13 | 12 | Regular Gasoline | Rear-Wheel Drive | 5.7L 8-cyl | Manual 4-spd |
| C2500 Sierra 2WD | 11 | 17 | 13 | Regular Gasoline | Rear-Wheel Drive | 5.7L 8-cyl | Manual 5-spd |
| C2500 Sierra 2WD | 15 | 20 | 17 | Diesel | Rear-Wheel Drive | 6.2L 8-cyl | Automatic 4-spd |
| C2500 Sierra 2WD | 16 | 18 | 17 | Diesel | Rear-Wheel Drive | 6.2L 8-cyl | Manual 4-spd |