Mazda 3 2020 Owner's Manual page 115

NOTE
(Premium unleaded fuel (within E85))
To maintain good engine startability and performance, the following points must be
observed.
Refuelling using the same-type fuel is recommended.

Add 16 L (4.2 US gal, 3.5 Imp gal) or more of fuel when refuelling.

Drive the vehicle 10 km (6.2 mile) or more just after refuelling to allow the

vehicle's engine control system to learn the ethanol concentration accurately.
Before Driving
Fuel and Emission
3-29