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: High Beam Control System (HBC) (Some models)
The High Beam Control System (HBC) determines the conditions in front of the vehicle using the Forward Sensing Camera (FSC) while driving in darkness to automatically switch the headlights between high and low beams. Refer to Warning/Indicator Lights. While driving the vehicle at a speed of ab ...

Mazda 6 Service Manual: Heated oxygen sensor (ho2s) inspection
HO2S Voltage Inspection Note Perform the following inspection only when directed. 1. Warm up the engine and run it at idle. 2. Disconnect the HO2S connector. 3. Connect the voltmeter test leads to the following HO2S terminals: HO2S (front and rear) - (+) leadterminal A - (-) le ...