Gas Type by Car: Regular, Premium, Diesel or E85 / Jeep / GladiatorJeep Gladiator Gas type by year YearGas type2027Regular2026Regular2025Regular2024Regular2023Depends on engine: diesel or regular2022Depends on engine: diesel or regular2021Depends on engine: diesel or regular Source: U.S. EPA / DOE fuel economy data (fueleconomy.gov).