
No.6 low maximum speed and poor acceleration no.7 no shifting
No.8 does not shift to fourth gear (4gr)Mazda 6 Service Manual: Heater core inspection
1. Remove the A/C unit. (See A/C UNIT REMOVAL/INSTALLATION.)
2. Remove the heater core from the A/C unit.
3. Inspect for cracks, damage, and coolant leakage.
If any problems are found, replace the heater core.
4. Inspect for bent fins.
If any are bent, use a flathead screwdriver to stra ...
Mazda 6 Service Manual: Recommendations for Shifting
Upshifting
For normal acceleration and cruising, Mazda recommends these shift points:
*1 Always observe local speed limit regulations.
Downshifting
When you must slow down in heavy traffic or on a steep upgrade, downshift before
the engine starts to overwork. This gives better acceleration w ...