1. Verify that the joint shaft is not twisted or cracked.
2. Turn the joint shaft by hand and verify that the bearing rotates smoothly and freely.

Drive shaft
Joint shaft removal/installationMazda 6 Service Manual: Idle air control (iac) valve inspection
Note
Perform the following inspection only when directed.
Operation Test
Carry out the Idle Air Control Inspection. (See Idle Air Control System
Inspection.)
If not as specified, perform the further inspection for the IAC valve.
Resistance Inspection
1. Disconnect the negative batt ...
Mazda 6 Service Manual: Recommendations for Shifting
Upshifting
For normal acceleration, Mazda recommends these shift points:
For cruising, Mazda recommends these shift points:
Downshifting
When you must slow down in heavy traffic or on a steep upgrade,
downshift before the engine starts to overwork. This reduces the chance of stalling
and ...