Use the documented fuel grade
The referenced 2020 Mazda3 manual specifies regular unleaded gasoline rated at least 87 AKI, also expressed as 91 RON. This guide applies to the naturally aspirated 2.5-liter configuration in PHTM’s catalog, not a later turbo model.
Sources 1
Check ethanol separately
That manual permits no more than 10 percent ethanol and excludes methanol-containing gasoline. A pump’s octane number does not tell you its ethanol percentage. Read both labels before selecting fuel.
Sources 1
Avoid unnecessary additives
Mazda cautions against adding fuel-system additives without consulting the dealer. More expensive fuel is not a substitute for diagnosing poor running, and PHTM does not claim premium produces a measurable gain in this application. If the engine runs poorly after refueling, preserve the receipt and seek diagnosis rather than experimenting with mixtures.
Sources 1
Sources / references 1
- Manufacturer technical reference ↗Reviewed Oct 6, 2026
Questions about this guide?
Share your vehicle details and what you have tried. Community posts are moderated; technical answers require verification.
Related discussions → · Ask a question →