What are the symptoms of excessive carbon deposits?

[Elliana]

Symptoms of excessive carbon deposits: 1. Difficulty starting the engine when cold, requiring multiple attempts, while starting normally when warm; 2. Unstable engine idling, with fluctuating RPMs; 3. Poor acceleration response when revving in neutral, accompanied by a sluggish feeling; 4. Reduced driving power, especially noticeable during overtaking, with slow acceleration response and failure to reach the vehicle's original power level; 5. Eye-irritating and pungent exhaust emissions that severely exceed standards; 6. Increased fuel consumption compared to before. Hazards of engine carbon deposits: 1. When carbon deposits adhere to spark plugs, they affect spark quality and may even prevent sparking; 2. When carbon deposits adhere to oxygen sensors, they prevent the sensors from accurately detecting exhaust conditions, leading to incorrect air-fuel ratio adjustments and excessive engine emissions; 3. When carbon deposits form inside the intake manifold, they roughen the interior surfaces, affecting the formation and concentration of the combustible air-fuel mixture.