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: Sunroof relay inspection
Note
Sunroof relay is built in the sunroof motor.
1. Remove the headliner. (See HEADLINER REMOVAL/INSTALLATION.)
2. Connect the sunroof switch connector.
3. Measure the voltage at the sunroof relay terminals as indicated below.
4. Disconnect the sunroof relay connector before inspecting fo ...
Mazda 6 Owners Manual: Variable intake-air system (vis) control solenoid valve inspection (l3)
1. Remove the VIS control solenoid valve. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
2. Inspect airflow between the ports under the following conditions.
If not as specified, replace the VIS control solenoid valve.
If as specified, carry out the Circuit Open/Short Inspection.
Circ ...