What Does Unstable Idle Speed Mean?
1 Answers
Unstable idle speed refers to the fluctuation of the tachometer needle when the engine is idling, accompanied by noticeable engine vibration. The causes of unstable idle speed include: 1. Improper air-fuel mixture ratio in the engine compartment; 2. Prolonged use of spark plugs leading to aging of ignition coils, high-voltage wire degradation, and leakage issues, which reduce ignition capability; 3. Carbon buildup on the engine's valves and intake ducts, which absorbs a portion of the injected fuel-air mixture, thereby reducing engine power; 4. Malfunctioning coolant temperature sensor. Solutions for unstable idle speed are: 1. Replace spark plugs; 2. Clean valves and intake ducts; 3. Inspect the coolant temperature sensor.