What Causes a Car to Shake at Idle and Then Stall?

[StAllison]

The reasons for a car shaking at idle and then stalling: 1. Excessive carbon deposits causing pre-ignition and knocking, shortening the engine's lifespan and significantly reducing its power and fuel efficiency; 2. Carbon deposits on the valve and its seat surface, leading to incomplete valve closure and air leakage, resulting in difficulties starting the engine, lack of power, and valve erosion; 3. Carbon deposits and gumming on the valve guide and valve stem, accelerating wear between the valve stem and guide, and even causing the valve stem to stick or seize in the guide, leading to valve sticking faults; 4. Excessive carbon deposits on the spark plugs, causing spark plug leakage, failure to operate, and engine shaking.