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: Component Parts
Microphone (hands-free) The microphone is used for speaking voice commands or when making a Hands-free call. Talk button, Pick-Up button and Hang-Up button (hands-free) The basic functions of Bluetooth® Hands-Free can be used for such things as making calls or hanging up using the talk, pi ...

Mazda 6 Service Manual: Fuse Panel Description
Fuse block (Engine compartment)           *Some models. Fuse block (Left side)         *Some models. ...