← all 2003 GMC Sierra 1500 2WD trims
2003 GMC Sierra 1500 2WD — 5.3L 8-cyl, Automatic 4-spd, RWD
This 2003 GMC Sierra 1500 2WD (5.3L 8-cyl, Automatic 4-spd, RWD) is flex-fuel (gasoline or E85). FLEX-FUEL
This 2003 model was originally EPA-tested under the pre-2008 2-cycle method, which didn't account for highway speeds over 60 mph, air-conditioner use, or cold starts. When EPA overhauled the test for model year 2008, city ratings fell by about 12% and highway by about 8% on average industry-wide — and EPA retroactively adjusted every 1984-2007 rating to the stricter standard so old and new cars could be compared fairly. The MPG above is already on that modern scale — the window sticker on this car when it was new likely showed a higher, pre-2008-method number.
Other 2003 GMC Sierra 1500 2WD trims
| Trim | Fuel | MPG | Fuel/yr |
|---|---|---|---|
| 4.3L 6-cyl, Automatic 4-spd, RWD | REGULAR | 16 | $3,562 |
| 4.3L 6-cyl, 5-spd manual, RWD | REGULAR | 16 | $3,562 |
| 4.8L 8-cyl, 5-spd manual, RWD | REGULAR | 16 | $3,562 |
| 4.8L 8-cyl, Automatic 4-spd, RWD | REGULAR | 15 | $3,800 |
| 5.3L 8-cyl, Automatic 4-spd, RWD | REGULAR | 15 | $3,800 |
EPA fuel type: Gasoline or E85 · class: Standard Pickup Trucks 2WD · engine: 5.3L 8-cyl · transmission: Automatic 4-spd · drive: RWD · MPG retrieved 2026-07-24.