What are the reasons for the lack of speed when accelerating in an old Mazda6?

[WyattFitz]

Specific reasons for the lack of speed when accelerating in an old Mazda6 are as follows: 1. Engine misfire: Engine misfire can lead to increased fuel consumption, black smoke emission, weak acceleration, and severe shaking. 2. Clutch slipping: The main cause of clutch slipping is insufficient friction on the clutch friction plate, resulting in gear shifting or disengagement before the clutch is fully engaged. 3. Low oil pressure: Low rail pressure often causes similar symptoms of weak acceleration and inability to increase RPM. 4. Dirty throttle position sensor or voltage imbalance: If the throttle position sensor is dirty or has a voltage imbalance, it can cause electronic throttle failure, resulting in the situation where the speed does not increase even when the throttle is fully pressed.