Mazda 6 Service Manual: No.4 hard to start/long crank/erratic start/erratic crank

No.3 will not crank

No.5 engine stalls-after start/at idle

Other materials:

Mazda 6 Service Manual: Engine Exhaust (Carbon monoxide)
WARNING Do not drive your vehicle if you smell exhaust gas inside the vehicle: Engine exhaust gas is dangerous. This gas contains carbon monoxide (CO), which is colorless, odorless, and poisonous. When inhaled, it can cause loss of consciousness and death. If you smell exhaust gas inside the ...

Mazda 6 Service Manual: Spark plug removal/installation
1. Disconnect the negative battery cable. 2. Remove the plug hoie plate. Lift off and remove the plug hole plate from the installation areas (rubber and clips) as shown in the figure. 3. Disconnect the high-tension lead. 4. Remove the spark plugs using the plug-wrench. 5. Install th ...