Upshifting
For normal acceleration and cruising, Mazda recommends these shift points:

*1 Always observe local speed limit regulations.
Downshifting
When you must slow down in heavy traffic or on a steep upgrade, downshift before the engine starts to overwork. This gives better acceleration when you need more speed.
On a steep downgrade, downshifting helps maintain safe speed and prolongs brake life.
Shift Gear (Shifting) Speed Limit
Direct ModeMazda 6 Owners Manual: Scheduled maintenance
SCHEDULED MAINTENANCE TABLE
For Europe (L.H.D. U.K.)
Chart symbols:
I : Inspect and repair, clean, adjust, or replace if necessary.
(Oil-permeated air cleaner elements cannot be cleaned using the air-blow
method.)
R : Replace
T : Tighten
L : Lubricate
Remarks:
To ensure efficient oper ...
Mazda 6 Owners Manual: Fuel tank inspection
Caution
Disconnecting/connecting the quick release connector without
cleaning it may possibly cause damage to the fuel pipe and quick release
connector. Always clean the quick release connector joint area before
disconnecting/connecting using a cloth or soft brush, and make sure that it ...