* Idle air control valve (IACV): The IACV is responsible for controlling the amount of air that bypasses the throttle valve when the engine is idling. If the IACV is faulty or dirty, it can cause the engine to idle too high.
* Throttle position sensor (TPS): The TPS tells the engine's computer how far the throttle is open. If the TPS is faulty or misadjusted, it can cause the engine to rev up too high when you start it.
* Vacuum leak: A vacuum leak can cause the engine to run lean, which can lead to high RPMs. Check for any leaks in the vacuum lines or connections.
* Faulty ignition system: If the spark plugs, wires, or distributor cap are faulty, it can cause the engine to misfire, which can also lead to high RPMs.
If you are experiencing this issue, it is best to have it diagnosed by a mechanic to determine the exact cause.
