Mazda 6 Service Manual: No.6 cranks normally but will not start

No.5 engine stalls-after start/at idle

No.7 slow return to idle

Other materials:

Mazda 6 Service Manual: Immobilizer System
The immobilizer system allows the engine to start only with a key the system recognizes. If someone attempts to start the engine with an unrecognized key, the engine will not start, thereby helping to prevent vehicle theft. If you have a problem with the immobilizer system or the key, consult ...

Mazda 6 Service Manual: Settings
NOTE Depending on the grade and specification, the screen display may differ. Select the icon on the home screen and display the Settings screen. Switch the tab and select the setting item you want to change. You can customize settings in the setup display as follows: ...