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: Using Automatic Locking Mode (Some models)
Follow these instructions when using a child-restraint system, unless you are attaching a LATCH-equipped childrestraint system to the rear LATCH lower anchors. Refer to “Using LATCH Lower Anchor”. NOTE Follow the child-restraint system manufacturer's instructions carefully. If you are no ...

Mazda 6 Service Manual: Drive Selection (Some models)
Drive selection is a system to switch the vehicle's drive mode. When the sport mode is selected, vehicle's response against accelerator operation is enhanced. This provides additional quick acceleration which may be needed to safely make maneuvers such as lane changes, merging onto freeways, o ...