Why does the Audi A4L make a gurgling sound at idle?

[LillianaAnn]

Audi A4L has abnormal noise at idle due to incomplete combustion of gas and prolonged idling. Below are the specific reasons: Incomplete combustion of gas: When the engine is idling, the mixture of gasoline and air in the combustion chamber cannot be completely burned, resulting in abnormal noise at the exhaust pipe. Prolonged idling: Long-term idling of the vehicle leads to excessive carbon deposits and dirt in the engine throttle and intake tract, reducing the area of the intake passage. This causes the vehicle's computer control unit to be unable to precisely control the intake volume, resulting in either too high or too low mixture concentration. The engine shakes due to abnormal combustion, and internal components such as the starter claw, half-moon key, crankshaft pulley, gasket, and motor belt collide with each other, generating abnormal noise.