2008 GMC Sierra C15 2WD MPG & Specs — Real-World vs EPA, All Trims
It depends on the trim. Some versions take premium and some take regular — check your exact engine/transmission below.
Is the 2008 GMC Sierra C15 2WD good on gas?
At up to 17 MPG combined, the 2008 GMC Sierra C15 2WD is about average for a Standard Pickup Trucks 2WD — that class averages about 17.3 MPG across 1,486 EPA-tested versions, so it's middle-of-the-road 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.
At today's AAA national average price — $3.80/gal for regular gas as of 2026-07-05 — the most efficient trim runs about $3,353/year (roughly $279/month, about $22.35 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 882 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 →
2008 GMC Sierra C15 2WD trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 4.3L 6-cyl, Automatic 4-spd, RWD | REGULAR | 17 | $3,353 |
| 5.3L 8-cyl, Automatic 4-spd, RWD | REGULAR | 17 | $3,353 |
| 4.8L 8-cyl, Automatic 4-spd, RWD | REGULAR | 16 | $3,562 |
| 6.0L 8-cyl, Automatic 4-spd, RWD | REGULAR | 15 | $3,800 |
| 5.3L 8-cyl, Automatic 4-spd, RWD | FLEX-FUEL | 17 | $3,650 |
| 6.2L 8-cyl, Automatic 6-spd, RWD | PREMIUM | 15 | $4,680 |
2008 GMC Sierra C15 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 · 5.3L 8-cyl · 4.8L 8-cyl · 6.0L 8-cyl · 6.2L 8-cyl |
| Transmission | Automatic 4-spd · Automatic 6-spd |
| Drive type | RWD |
| EPA body class | Standard Pickup Trucks 2WD |
| Fuel | Varies by trim |
Other years of the GMC Sierra C15 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.