What Causes High Idle Speed After Cleaning the Throttle Body?
2 Answers
The reason for high idle speed after cleaning the throttle body is that the throttle body has not been reset. Here is an introduction to the throttle body: Function: The throttle body controls the air entering the engine. After the air enters the intake pipe, it mixes with gasoline to form a combustible mixture, which then burns to generate power. Principle: The traditional throttle body operates via a cable (soft steel wire) or rod, with one end connected to the accelerator pedal and the other to the throttle linkage plate. An electronic throttle body mainly uses a throttle position sensor to control the throttle opening angle based on the engine's required energy, thereby regulating the intake air volume.
Common reasons for high idle speed after cleaning the throttle body include the throttle position sensor not yet adapting to the cleaned state, and the car's ECU may need to relearn the new position. When driving initially, the computer reads old data, causing the idle speed to be high or fluctuate. I've experienced this myself—right after cleaning, the engine RPM shot up upon starting. The solution is simple: drive the car normally on the road for about 20 minutes, and the computer will automatically recalibrate. If there's no improvement, check whether the throttle body is securely installed or if there's any dust residue. Improper handling during cleaning might temporarily disable the sensor. Additionally, take a look at the idle control valve or mass airflow sensor—if these parts are dirty, they can interfere with airflow control. Prolonged high idle speed can affect fuel consumption, so it's best not to delay addressing it. If you really can't fix it, take it to a professional shop to reset the computer settings with a diagnostic tool—it should recover quickly. Remember to let the car cool down completely before cleaning and handle it gently to avoid secondary contamination.
