What is coasting in neutral and coasting with clutch engaged in gear?

[DiJesse]

When coasting in neutral, the engine power output is completely disconnected from the transmission. To re-engage power, both the clutch and transmission must be operated together. When coasting with the gear engaged, the engine power output is partially disconnected, with the degree of disconnection controlled by the clutch engagement level. Below are detailed explanations of coasting in neutral and coasting with clutch engaged in gear: 1. Coasting in neutral: Coasting in neutral must be performed under conditions of safety and normal vehicle technical status, and engine-off coasting is not permitted. Especially when descending steep or long slopes, neither engine-off coasting nor coasting in neutral is allowed. 2. Coasting with clutch engaged in gear: When the vehicle is coasting with the gear engaged and the foot is off the accelerator pedal, the engine speed will quickly drop to idle speed. The throttle position sensor detects this signal and transmits it to the computer, which then controls the fuel injection pulse width according to the designed idle conditions to maintain the engine at idle speed.

[ThomasRose]

Coasting in neutral refers to when driving a manual transmission car, the driver shifts the gear lever to the neutral position (N gear), allowing the vehicle to glide freely by inertia. At this point, the engine speed drops to idle, disengaging from driving, making the car feel as smooth as skating. Clutch-in coasting with gear engaged is different—it involves pressing the clutch pedal without changing gears, such as keeping it in fourth gear. This also disconnects the engine from the drivetrain, causing the engine to idle while the vehicle coasts. New drivers often use these methods for convenience, especially when going downhill or waiting at a red light, aiming to save fuel or make driving easier. However, it's important to note that coasting in neutral may increase braking distance due to the loss of engine braking assistance. In case emergency acceleration is needed, the vehicle's response will be slower. Therefore, it's not recommended to do this on highways or busy roads.

[LaTaylor]

Speaking of coasting in neutral and coasting with the clutch depressed in gear, the former involves shifting into neutral, allowing the car to glide solely on kinetic energy; the latter means pressing the clutch while remaining in gear, disengaging engine drive but keeping the gear unchanged. Many drivers use these techniques in traffic jams or on long descents, believing they can save a bit of fuel or reduce clutch wear. However, coasting in neutral carries significant risks. Once, while driving in mountainous terrain, I tried it—the car felt uncontrollable with reduced traction, and braking effectiveness dropped dramatically, especially dangerous in rain or snow. In contrast, coasting with the clutch depressed in gear is slightly safer, but frequent use can accelerate clutch disc wear and shorten the car's lifespan. From my experience, engine braking can still provide some assistance during gear coasting, whereas neutral coasting relies entirely on brakes—often more trouble than it's worth.

[AlejandroLee]

If you're asking about coasting in neutral versus coasting in gear with the clutch pressed, let me explain from a fuel-saving perspective: Coasting in neutral means shifting to N gear and letting the car glide, with the engine idling and consuming fuel; coasting in gear with the clutch pressed involves keeping the clutch depressed while in gear, with the engine also idling but potentially more economical. Nowadays, most cars automatically cut off fuel supply when coasting in gear, which is far more efficient than the continuous fuel consumption in neutral. From my own driving experience, coasting in gear noticeably reduces fuel consumption, especially between city traffic lights, whereas coasting in neutral can make speed control more stressful.