How to Lower High Idle Speed?
2 Answers
High idle speed can be adjusted at professional repair shops or 4S stores. Below is relevant information about high idle speed: 1. Causes: Mainly include damaged intake sensors, excessive vehicle air intake, faulty water temperature sensors (where the vehicle increases idle speed to raise water temperature), and throttle position sensor malfunctions. 2. Hazards: Prolonged idling can easily lead to carbon buildup. Since the car operates in a rich fuel injection state during idling, the injector sprays highly concentrated fuel to ensure engine operation. Therefore, idling itself is more likely to cause carbon buildup compared to driving or highway speeds. Extended idling can result in severe engine carbon deposits.
Last time my car had high idle speed and was consuming too much fuel, so I adjusted it myself. First, I turned off the engine and checked the air filter, finding it clogged—I immediately replaced it with a new one, which alleviated the problem. Next, I carefully cleaned the throttle body, using a specialized cleaner to spray and remove carbon deposits, avoiding damage to the components. Resetting the ECU was simple: I disconnected the battery for 10 minutes and then reconnected it, allowing the car to relearn the idle settings. This method is quite cost-effective, but don’t force it—wear gloves for protection during cleaning, use the right tools, and stop if it doesn’t work the first time to avoid damaging the wiring. Regular maintenance like this can save a lot of hassle. If the car is old or symptoms persist, it’s best to take it directly to a repair shop to test the idle control valve.
