Why does the throttle increase when the clutch is pressed?

[LouisFitz]

The reasons for the throttle increasing when the clutch is pressed are as follows: Clutch switch detachment: The clutch switch is detached or damaged, causing the engine speed to suddenly increase. When the clutch switch is engaged or disengaged, the engine control unit detects these signals to determine whether an increase in speed is necessary. If this signal malfunctions, the engine cannot make the correct judgment, so it increases the engine speed to prevent stalling during gear shifts. Vacuum line leak: A leak in the engine intake vacuum line causes the engine speed to rise and not decrease. This requires inspection and repair at a service center. Dirty throttle body: A dirty throttle valve body prevents the engine speed from decreasing.