Why does the engine make a rumbling sound?

[Robin]

Reasons for the engine making a rumbling sound. Exhaust pipe leakage: When there is a leak in the intake or exhaust pipe, the vehicle will produce a loud rumbling sound as the exhaust rate increases during acceleration. Dirty throttle valve: During acceleration, the engine load increases, requiring the throttle valve to open wider and more fuel to be injected. If the throttle valve is dirty and does not open to the optimal position, it can lead to poor air-fuel mixture ratio, resulting in noise during acceleration. Engine misfire: Engine misfire mainly refers to one or more cylinders not functioning properly. Common symptoms include insufficient vehicle power, severe shaking of the exhaust pipe, and a clear "popping" or rumbling sound from the engine.