- Check the idle air control (IAC) valve: The IAC valve is responsible for controlling the amount of air that bypasses the throttle body and enters the engine at idle. If it's not working properly, it can cause the engine to idle too low. Clean the IAC valve with a throttle body cleaner and check the electrical connection to the valve to make sure it's secure.
- Check for vacuum leaks: Vacuum leaks can cause the engine to run lean and can lead to a low idle. Inspect all of the vacuum lines and connections around the engine for any cracks, leaks, or damage. Replace any damaged or leaking lines.
- Clean the throttle body: A dirty throttle body can cause the engine to idle rough and can lead to a low idle. Use a throttle body cleaner to clean the throttle body and remove any dirt, grime, or carbon deposits.
- Check the throttle position sensor (TPS): The TPS is a sensor that tells the engine control module (ECM) how far the throttle is open. If the TPS is not working properly, it can send the wrong signal to the ECM, which can cause the engine to idle too low. Test the TPS with a multimeter to make sure it's sending the correct voltage signal to the ECM.
- Check the fuel pressure: Low fuel pressure can also cause the engine to run lean and can lead to a low idle. Check the fuel pressure with a fuel pressure gauge to make sure it's within the specified range.
If you've checked all of these things and the low idle problem persists, it's best to consult a qualified mechanic who can further diagnose the issue.
