Health check
1. Set the engine to idle and warm it up to operating temperature. Disconnect the throttle control vacuum hose. In this case, the engine speed should increase to 2200 rpm for a manual gearbox and up to 1900 rpm for an automatic transmission in position N. If the speed is higher, then it should be adjusted by appropriately bending the key.
2. If the rotation speed does not increase, then check for vacuum in the hose. If there is a vacuum, then the throttle control is faulty. If there is no vacuum, then somewhere there has been a leak, or the hose is not connected correctly.