Does the 2003 Isuzu Ascender 4WD need premium gas?
Every trim takes regular — no premium needed.
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr |
|---|---|---|---|
| 4.2L 6-cyl, Automatic 4-spd, AWD | REGULAR | 15 | $4,150 |
| 5.3L 8-cyl, Automatic 4-spd, AWD | REGULAR | 14 | $4,450 |
The EPA records the fuel each version was tested on. Whether premium is strictly required or just recommended is an owner's-manual detail the EPA dataset doesn't include — so we don't guess it.
2 trim(s) · EPA FuelEconomy.gov · retrieved 2026-06-14.