What are the symptoms of excessive engine carbon deposits?

[ConnorLee]

Carbon deposits are mainly formed due to incomplete combustion of gasoline and frequent low-speed operation of the vehicle. Excessive carbon deposits in a car can cause the following symptoms: 1. Engine vibration: The engine produces intermittent and regular vibrations when idling. 2. Unstable engine idle: The engine speed fluctuates erratically when idling, sometimes high and sometimes low. 3. Weak engine acceleration: When carbon deposits accumulate severely, the engine may exhibit weak or sluggish acceleration, accompanied by abnormal vibrations and increased fuel consumption. 4. Engine knocking: If carbon deposits accumulate excessively in the combustion chamber, the engine's compression ratio may increase, potentially causing premature combustion of the air-fuel mixture and resulting in knocking. 5. Cylinder scoring: If carbon deposits accumulate near the piston rings or if carbon deposits from the cylinder head or valves fall onto the piston rings, it can lead to cylinder scoring. In severe cases, it may even cause the engine to "seize up."