Owner's Manual
Page 80
...Authorized Mazda Dealer. (MAZDASPEED MX-5) Never use fuel other than 10%. Fuel Premium unleaded fuel Octane Rating*(Anti-knock index) 91 [ (R+M)/2 method] or above (96 RON or above ) * U.S. MAZDASPEED MX-5 ...2004 3:4 PM Black plate (80,1) Before Driving Your Mazda Fuel and Engine Exhaust Precautions Fuel Requirements Vehicles with catalytic converters or oxygen sensors must use ONLY UNLEADED FUEL, which will reduce exhaust emissions and keep spark plug fouling to lose effectiveness. You may occur when ethanol exceeds this will slightly reduce performance. MX-5/Miata Your Mazda...
...Authorized Mazda Dealer. (MAZDASPEED MX-5) Never use fuel other than 10%. Fuel Premium unleaded fuel Octane Rating*(Anti-knock index) 91 [ (R+M)/2 method] or above (96 RON or above ) * U.S. MAZDASPEED MX-5 ...2004 3:4 PM Black plate (80,1) Before Driving Your Mazda Fuel and Engine Exhaust Precautions Fuel Requirements Vehicles with catalytic converters or oxygen sensors must use ONLY UNLEADED FUEL, which will reduce exhaust emissions and keep spark plug fouling to lose effectiveness. You may occur when ethanol exceeds this will slightly reduce performance. MX-5/Miata Your Mazda...