1. Check under the hood area to make certain all filler caps are in place and all loose items (e.g. tools, oil containers, etc.) have been removed.
2. Lift the hood, grasp the padded area on the support rod, and secure the support rod in the clip. Verify that the support rod is secured in the clip before closing the hood.

3. Lower the hood slowly to a height of about 20 cm (7.9 in) above its closed position and then let it drop.
CAUTION
When closing the hood, do not push it excessively such as by applying your weight. Otherwise, the hood could be deformed.
Opening the HoodMazda 6 Owners Manual: Scheduled Maintenance (U.S.A., Canada, and Puerto Rico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following
conditions (severe driving conditions) apply.
Repeated short-distance driving
Driving in dusty conditions
Driving with extended use of brakes
Driving in areas where salt or other corrosive materials are used
...
Mazda 6 Owners Manual: No.4 air intake mode does not change
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while performing the inspection to discover
whether poor contact points are the cause of any intermittent malfunctions.
If there is a problem, check to make sure connectors, terminal ...