Why is there abnormal noise when releasing the throttle but not when accelerating?

[MacAlexander]

Abnormal noise when releasing the throttle but not when accelerating is due to issues with the car's half-shaft. Reasons for the buzzing sound when pressing the accelerator: It's not an engine problem, but rather caused by loose nuts on the front drive shaft; The device on the internal combustion engine that controls fuel supply; The throttle pedal is also known as the accelerator pedal. Introduction to hazard handling: In case of throttle pedal issues during new car operation, don't panic. As professionals suggest, fully depress the brake pedal to stop the vehicle, then turn off the engine and contact for assistance. When climbing a slope, avoid fully depressing the throttle pedal; when using low gear, it's generally advisable to press the throttle halfway.

[AugustFitz]

I've encountered similar issues while driving. When I release the accelerator, I hear a humming or clicking sound from under the car, but it quiets down when I press the accelerator. This might be related to the suspension system, especially aging shock absorbers or loose suspension joints. When the accelerator is released and the car suddenly decelerates, these components experience pressure changes, making them prone to friction noises. Additionally, worn wheel bearings could also cause similar phenomena, as vibrations intensify when the load is reduced. I remember the noise disappeared after I replaced a front shock absorber last time—it wasn't expensive but very effective. I recommend getting your suspension components checked at a repair shop. Avoid sudden acceleration or braking in daily driving to prolong the suspension's lifespan. Delaying this issue might lead to unstable vehicle conditions, so it's better to address it sooner.

[DelNora]

As someone who frequently works on cars, I've observed that this type of abnormal noise mostly originates from exhaust system failures, such as aging exhaust pipe hangers or damaged gaskets. When you release the throttle, engine vibration decreases, causing the exhaust pipe to sway more freely and produce noise; whereas when you step on the throttle, increased vibration suppresses the noise. Other possibilities include worn universal joints in the driveshaft, which creak under changing loads. Don't overlook small components—repairs are actually inexpensive, with a new hanger costing just a few hundred yuan. Regularly inspect exhaust pipe connection points and engine mounts to ensure there's no rust or looseness, which is crucial for preventing abnormal noises. From a safe driving perspective, if the noise intensifies, it's best to avoid high-speed driving to prevent sudden component detachment.

[LeHailey]

Having driven for decades, abnormal noises when releasing the throttle are often related to the drivetrain, such as worn differential bearings or loose half-shafts. When you let off the accelerator, the drivetrain load decreases, making worn components more prone to friction noise. Under acceleration when the system is under tension, the noise disappears. This isn't a major issue, but requires timely attention. Remember to inspect tires and chassis connection points - adding lubricant during maintenance can prevent similar issues. The cost is minimal, just requiring bearing replacement.