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: Antilock Brake System (ABS)
The ABS control unit continuously monitors the speed of each wheel. If one wheel is about to lock up, the ABS responds by automatically releasing and reapplying that wheel's brake. The driver will feel a slight vibration in the brake pedal and may hear a chattering noise from the brake system ...

Mazda 6 Service Manual: Radar Sensors (Rear) (Some models)
Your vehicle is equipped with radar sensors (rear). The following systems also use the radar sensors (rear). Blind Spot Monitoring system (BSM) Rear Cross Traffic Alert (RCTA) The radar sensors (rear) function by detecting the radio waves reflected off a vehicle approaching from the rea ...