What Causes Low Idle Speed in Vehicles?
2 Answers
Idle speed in a car does not refer to a specific speed, but rather to an operational condition. When the engine is running without load, it is referred to as idling. The reasons for low idle speed in vehicles include: 1. Malfunction of the idle speed control valve. 2. Poor atomization or clogging of the fuel injectors. 3. Changes in oil viscosity. The hazards of excessively low idle speed are as follows: 1. Low idle speed makes it easier for the engine to stall when starting, and frequent use of the starter is detrimental to both the engine and the starter. 2. Low idle speed can lead to stalling during gear shifts while driving, which is very dangerous. This is particularly risky when following other vehicles closely, as it increases the likelihood of rear-end collisions. 3. Engine shaking at idle causes significant wear and tear on the engine.
I've personally experienced low idle speed several times, and it's particularly annoying. When parked, the engine RPM drops below 500, causing the car to shake violently as if it's about to stall at any moment—it's really nerve-wracking. Common causes include excessive carbon buildup in the throttle body, leading to insufficient airflow and unstable power; aging spark plugs affecting ignition efficiency; and low or fluctuating battery voltage disrupting idle balance. If the idle control valve gets stuck and can't adjust, the situation worsens. Regular cleaning of key components is recommended, such as using spray to remove carbon deposits from the throttle body. Otherwise, low idle speed not only increases fuel consumption but may also damage internal engine components over time.
