2020 GMC Sierra 2WD MPG & Specs — Real-World vs EPA, All Trims
Fuel grade varies by trim — see the breakdown below.
Is the 2020 GMC Sierra 2WD good on gas?
At up to 26 MPG combined, the 2020 GMC Sierra 2WD is better than average for a Standard Pickup Trucks 2WD — that class averages about 17.3 MPG across 1,486 EPA-tested versions, so it's a good pick on fuel 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 $2,714/year (roughly $226/month, about $18.10 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 714 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 →
2020 GMC Sierra 2WD trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 2.7L 4-cyl, Automatic 8-spd, RWD | REGULAR | 21 | $2,714 |
| 2.7L 4-cyl, Automatic 8-spd, RWD | REGULAR | 20 | $2,850 |
| 5.3L 8-cyl, Automatic 8-spd, RWD | REGULAR | 20 | $2,850 |
| 5.3L 8-cyl, Automatic 8-spd, RWD | REGULAR | 19 | $3,000 |
| 4.3L 6-cyl, Automatic 6-spd, RWD | REGULAR | 17 | $3,353 |
| 5.3L 8-cyl, Automatic 6-spd, RWD | REGULAR | 17 | $3,353 |
| 3.0L 6-cyl, Automatic 10-spd, RWD | DIESEL | 26 | $2,758 |
| 5.3L 8-cyl, Automatic 6-spd, RWD | FLEX-FUEL | 16 | $3,900 |
2020 GMC Sierra 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 | 2.7L 4-cyl turbo · 5.3L 8-cyl · 4.3L 6-cyl · 3.0L 6-cyl turbo |
| Transmission | Automatic 8-spd · Automatic 6-spd · Automatic 10-spd |
| Drive type | RWD |
| EPA body class | Standard Pickup Trucks 2WD |
| Fuel | Varies by trim |
| Tailpipe CO₂ | 392–545 g/mi |
Other years of the GMC Sierra 2WD
Similar cars (Standard Pickup Trucks 2WD)
Cars that take premium · Cheapest cars to fuel · Where fuel grade depends on the trim · Fuel guides
8 trim(s) · EPA FuelEconomy.gov data retrieved 2026-07-24 · fuel prices AAA national average as of 2026-07-05.