What causes high engine RPM when depressing the clutch to shift gears?

[NolanMarie]

The reasons for high engine RPM when depressing the clutch to shift gears are as follows: 1. Normally when shifting gears, you should simultaneously depress the clutch and release the accelerator. The moment the power is cut off, the engine RPM begins to decrease. If the accelerator is released too early, the engine RPM may drop first, potentially causing engine braking and resulting in a jerking sensation, similar to suddenly stepping on the brakes. If the accelerator is released too late when the clutch is already disengaged, continuing to press the accelerator with no load on the engine will inevitably cause the RPM to rise. 2. Since the vehicle is in motion, the idle speed will be slightly higher due to the ECU's idle compensation function. When you depress the clutch, the engine load is removed, and the operating resistance instantly decreases, so the engine's rotational force increases, causing the RPM to rise. It's like pulling an object forward with a rope - if the rope is suddenly cut, you would lurch forward abruptly. When the RPM rises beyond the target idle speed, the ECU will intervene to restore the idle speed to the target level for the current operating condition.