1. An engine vacuum leak: It can cause the engine to raise the RPMs when pushing the clutch pedal. Look for disconnected engine vacuum hoses or a crack in the hose itself.
2. Damaged mass air flow sensor. Mass air flow sensor readings are crucial to a vehicle's air-fuel ratio. If it's malfunctioning, the engine could respond to pushing the clutch in by raising RPMs.
3. Idle air control valve (IAC) issues. The IAC valve maintains the engine's idle RPM. If it's faulty or stuck, the engine could rev high when disengaging the clutch while idling.
It's important to get the source of this issue accurately diagnosed and addressed to prevent unnecessary engine stress.
