← all 2018 GMC Sierra K15 4WD trims
2018 GMC Sierra K15 4WD — 5.3L 8-cyl, Automatic 8-spd, 4WD
This 2018 GMC Sierra K15 4WD (5.3L 8-cyl, Automatic 8-spd, 4WD) takes regular (87-octane) gasoline. REGULAR
17
MPG combined (15 city / 20 hwy)
$3,353
est. fuel cost / year (today’s prices, 15k mi)
522 g/mi
tailpipe CO₂
At today's AAA national average price ($3.80/gal, 2026-07-05) — the EPA's own price/date assumption isn't exposed in the public dataset, so we recompute this from the EPA's MPG figure and a sourced current price.
Other 2018 GMC Sierra K15 4WD trims
| Trim | Fuel | MPG | Fuel/yr |
|---|---|---|---|
| 5.3L 8-cyl, Automatic 6-spd, 4WD | REGULAR | 18 | $3,167 |
| 4.3L 6-cyl, Automatic 6-spd, 4WD | FLEX-FUEL | 19 | $3,300 |
| 5.3L 8-cyl, Automatic 6-spd, 4WD | FLEX-FUEL | 18 | $3,450 |
| 6.2L 8-cyl, Automatic 8-spd, 4WD | PREMIUM | 17 | $4,129 |
EPA fuel type: Regular · class: Standard Pickup Trucks 4WD · engine: 5.3L 8-cyl · transmission: Automatic 8-spd · drive: 4WD · MPG retrieved 2026-07-24.