Mazda 6 Service Manual: No.7 slow return to idle

No.6 cranks normally but will not start

No.8 engine runs rough/rolling idle

Other materials:

Mazda 6 Service Manual: Generator removal/installation
Warning When the battery cables are connected, touching the vehicle body with generator terminal B will generate sparks. This can cause personal injury, fire, and damage to the electrical components. Always disconnect the battery negative cables before performing the following operation. ...

Mazda 6 Service Manual: Hill Launch Assist (HLA)
Hill Launch Assist (HLA) is a function which assists the driver in accelerating from a stop while on a slope. When the driver releases the brake pedal and depresses the accelerator pedal while on a slope, the function prevents the vehicle from rolling. The braking force is maintained automatic ...