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: Front Seat Belt Pretensioner and Load Limiting Systems
For optimum protection, the driver and front passenger seat belts are equipped with pretensioner and load limiting systems. For both these systems to work properly you must wear the seat belt properly. Pretensioners: When a collision is detected, the pretensioners deploy simultaneously with th ...

Mazda 6 Service Manual: Front seat belt removal/installation
Warning Handling the front seat belt (pre-tensioner seat belt) improperly can accidentally deploy the pre-tensioner, which may seriously injure you. Read SERVICE WARNINGS before handling the front seat belt. (See SERVICE WARNINGS.) Warning The side air bag sensor is attached to t ...