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: Side air bag sensor removal/installation
Warning Handling the side air bag sensor improperly can accidentally deploy the side air bag module, which may seriously injure you. Read AIR BAG SYSTEM SERVICE WARNINGS before handling the side air bag sensor. (See SERVICE WARNINGS.) 1. Turn the ignition switch to LOCK position. 2. ...

Mazda 6 Service Manual: General procedures
PRECAUTION (SUSPENSION) Wheels and Tires Removal/Installation When a wheel is installed, tighten it to 88-118 N·m {9.0-12.0 kgf·m, 65.0-87.0 ft·lbf}. Suspension Links Removal/Installation Tighten any part of the suspension that uses rubber bushings only after the vehicle has been lowered ...