Reasons for High Engine Idle Speed in Cars?
2 Answers
Reasons for high engine idle speed in cars are as follows: 1. ECT sensor malfunction. 2. AC switch or air conditioning refrigerant pressure sensor malfunction. 3. Throttle body or throttle position sensor signal failure. 4. Automatic transmission neutral switch malfunction. 5. Intake system air leakage. 6. Accelerator pedal position sensor (APP) malfunction. Methods for troubleshooting high engine idle speed are as follows: 1. Test the ECT sensor and replace if necessary. 2. Replace the AC switch or air conditioning refrigerant pressure sensor; replace the throttle body. 3. Adjust the automatic transmission and replace the switch if necessary; replace the intake hose. 4. Repair or adjust.
Last time my car's idle speed suddenly rose very high, which was obviously abnormal. The possible causes of high idle speed include a faulty throttle position sensor—that thing controls the air intake, and if it's broken, it lets in more air, increasing the RPM. Or the idle control valve could be stuck open too wide, causing excessive airflow. Air leaks in the intake pipe are also common culprits, as tiny cracks let extra air in that the ECU can't detect as an error. High idle speed can cause fuel consumption to skyrocket, wasting money and making engine temperatures unstable, increasing the risk of overheating. I've dealt with it myself by cleaning the valve body and checking the sensor connections, which fixed the issue. But in severe cases, it's best to go to a professional shop to scan for trouble codes with a diagnostic tool, ensuring safe driving and avoiding breakdowns on the road.
