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: Cylinder head gasket
CYLINDER HEAD GASKET REPLACEMENT Warning Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel ...

Mazda 6 Service Manual: Engine control system operation inspection
Main Relay Operation Inspection Verify that the main relay clicks when the ignition switch is turned to ON position and off. If there is no operation sound, inspect the following. - Main relay (See RELAY INSPECTION.) - Harness and connector between ignition switch and main relay termi ...