1. Inspect the dust boot on the drive shaft for cracks, damage, leaking grease, and looseness in the boot band.

2. Inspect the drive shaft for bends, cracks, and wear in the joint or splines.
Joint shaft disassembly/assembly
Drive shaft removal/installationMazda 6 Service Manual: Installation of radio system
If a radio system is installed improperly or if a high-powered type is used,
the CIS and other systems may be affected. When the vehicle is to be equipped
with a radio, observe the following precautions:
Install the antenna at the farthest point from control modules.
Install the antenna fe ...
Mazda 6 Service Manual: Floor Mat
We recommend the use of Genuine Mazda floor mats.
WARNING
Make sure the floor mats are hooked on the retention pins to prevent them
from bunching up under the foot pedals: Using a floor mat that is not secured
is dangerous as it will interfere with the accelerator and brake pedal operation,
...