What Causes the Buzzing Noise When Accelerating That Stops When Letting Off the Throttle?

[OLucille]

The reasons for the buzzing noise when accelerating that stops when letting off the throttle are: 1. The accessory belt of the car is too loose, causing increased load and belt noise when accelerating; 2. Carbon buildup in the car's throttle body leads to poor throttle response, and the idle control valve and throttle plate are too dirty; 3. There is a mixture of carbon deposits and engine oil in the car's engine intake tract, causing a buzzing noise when accelerating. The solutions are: 1. Check the generator belt, compressor belt, power steering pump belt, etc., and replace or tighten them if loose; 2. Inspect the car's throttle body, clean and recalibrate if dirty; 3. Clean the mixture of oil and carbon deposits in the intake tract using a specialized intake tract cleaner; 4. Check if the throttle pedal spring is loose or fatigued, and replace it as soon as possible if necessary.

[Rick]

I just encountered a similar issue at the repair shop last week! When you step on the gas pedal, there's a buzzing sound from the chassis that disappears when you release the throttle, right? It's most likely an exhaust system resonance. Focus on checking the rubber hangers in the middle section of the exhaust pipe for aging or cracking (especially in older cars with over 100,000 km), or if the exhaust was modified without adding vibration-damping spacers. Also, for front-wheel-drive cars, pay special attention to leaking CV joint boots—worn-out CV joints can cause a clunking sound when accelerating. My own car had this issue, and replacing the exhaust hanger rubber pads fixed the noise problem for just 80 bucks.

[PeterDella]

This issue can be analyzed from three aspects: The most common cause is an air leak in the intake pipe, loose clips on the air filter box, or a cracked turbo pipe, which can produce a whistle-like buzzing sound during high-speed air intake. Secondly, it could be due to aged engine mount bushings. I once repaired an 8-year-old Corolla where the engine would sink and press against the mounts during acceleration, causing vibration and abnormal noises. Another possibility is bearing issues. Damaged wheel bearings or alternator bearings can produce noise at specific RPM ranges. Using a stethoscope against engine compartment components can accurately pinpoint the source.

[ElisaLynn]

Based on my experience handling over a hundred cars with abnormal noises: prioritize checking the tires! Uneven tread wear forming sawtooth-shaped edges can create resonance noise at speeds above 70km/h. Next, inspect the transmission mount rubber—especially noticeable in manual transmission cars during semi-engagement acceleration. Also, don’t overlook the fuel pump in the tank; when fuel pressure increases, the pump's hum can penetrate the cabin. A simple verification method is to rev the engine in neutral—if the noise persists, you can rule out drivetrain issues.