2003 GMC Sierra 1500 2WD MPG & Specs — Real-World vs EPA, All Trims
Fuel grade varies by trim — see the breakdown below.
Is the 2003 GMC Sierra 1500 2WD good on gas?
At up to 16 MPG combined, the 2003 GMC Sierra 1500 2WD is worse than average for a Standard Pickup Trucks 2WD — that class averages about 17.3 MPG across 1,486 EPA-tested versions, so it's on the thirsty side for its size.
Real-world MPG vs the EPA number
The EPA figures above come from a standardized dynamometer test, not the open road — real-world MPG typically runs a bit lower depending on your driving, climate and terrain. That's true of every car on this site, old or new.
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.
At today's AAA national average price — $3.80/gal for regular gas as of 2026-07-05 — the most efficient trim runs about $3,562/year (roughly $297/month, about $23.75 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 938 gallons a year. We don't estimate a cost-per-fill since exact tank size isn't in the public EPA dataset, but the per-100-mile figure scales to any tank. Current national average gas prices →
2003 GMC Sierra 1500 2WD trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 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 |
| 5.3L 8-cyl, Automatic 4-spd, RWD | FLEX-FUEL | 15 | $4,150 |
2003 GMC Sierra 1500 2WD specs
What the EPA test-car listings record for this model year — every combination sold is a row in the trims table above.
| Engine options | 4.3L 6-cyl · 4.8L 8-cyl · 5.3L 8-cyl |
| Transmission | Automatic 4-spd · 5-spd manual |
| Drive type | RWD |
| EPA body class | Standard Pickup Trucks 2WD |
| Fuel | Varies by trim |
Other years of the GMC Sierra 1500 2WD
Similar cars (Standard Pickup Trucks 2WD)
Cars that take premium · Cheapest cars to fuel · Where fuel grade depends on the trim · Fuel guides
6 trim(s) · EPA FuelEconomy.gov data retrieved 2026-07-24 · fuel prices AAA national average as of 2026-07-05.