Is Idle Speed the Same as Neutral Gear?

[MacXavier]

Idle speed is indeed neutral gear. Idle speed refers to an operational state of the car where the engine runs without being engaged in any gear. The rotational speed of the engine during idle is known as the idle speed, which can be adjusted by modifying parameters such as the throttle opening. Essentially, idle speed means the engine is running but not doing any work. Common causes of car idle vibration include engine carbon buildup, aging or fouled spark plugs, dirty engine throttle body, clogged fuel lines, and ignition system malfunctions. Engine carbon buildup results from various factors, but poor driving habits are the primary cause. Components like ignition coils, spark plugs, and high-voltage wires have limited lifespans, and any issues with them can lead to ignition system inefficiencies, resulting in idle vibration.

[LucyLee]

This is a question I often get asked. After driving for many years, many people still can't tell the difference between idling and neutral gear. Idling is not the same as neutral. Idling refers to the state where the engine is running at low speed, such as when you stop at a red light and the engine is still quietly running, maintaining a speed of a few hundred RPM. Neutral, on the other hand, is a gear position in the transmission—when you shift the gear lever to the N position, the connection between the engine and the wheels is disconnected. The car won't move, but the engine can still idle. In other words, when in neutral, the engine is usually idling, but idling doesn't necessarily only happen in neutral—for example, when you're in D gear and pressing the brake, the engine can also idle. Understanding this difference is important to avoid misoperation that could lead to wasted fuel or stalling. I recommend paying more attention to the RPM gauge on the dashboard while driving to familiarize yourself with which gear position allows the engine to idle most fuel-efficiently.

[Gray]

When I first started learning to drive, I had similar confusion, thinking idling was the same as being in neutral. They are actually two completely different things. Idling refers to the state where the engine is running at low RPM, such as when warming up or parked, consuming less fuel. Neutral is one of the transmission gears, and shifting to N means no power is transmitted to the wheels. The engine often idles when in neutral, but idling can also occur in P or D gear when the brake is pressed. I usually shift to neutral and let the engine idle when waiting at a red light to save fuel and keep things quiet. Beginners often mix them up, but with a bit more practice, it becomes clear. Avoid prolonged idling in D gear to prevent transmission wear.

[MacNolan]

Having driven for decades, idle speed and neutral gear are completely different concepts. Idle speed refers to the engine running at low RPM, while neutral gear is a transmission position. In daily driving, such as waiting at a long red light, I shift to N gear to let the engine idle. Idle state can occur in any gear position, whereas neutral gear is used to prevent power transmission. Understanding this distinction clearly can reduce the risk of misoperation.

[DelOlive]

Many people confuse idling with neutral gear, which can lead to safety hazards. Idling refers to the state where the engine runs at a low speed, while neutral gear is the position where the transmission cuts off power. Confusing the two may result in accidentally shifting into the wrong gear and coasting or overloading the engine. For safety, shifting into neutral when parked allows the engine to idle smoothly, and idling is most appropriate in the N position. Understanding this ensures a more stable driving experience.