What Causes Shaking During Acceleration in Automatic Transmission Cars?
1 Answers
Shaking during acceleration in an automatic transmission car may be caused by the following reasons: a dirty throttle body leading to uneven air intake and operation, clogged fuel lines causing insufficient fuel supply at low throttle resulting in uneven cylinder operation, or transmission malfunction. Below are detailed explanations: 1. Abnormal Shaking: If an automatic car shakes during startup but runs smoothly afterward, possible causes include: a dirty throttle body causing uneven air intake and shaking, clogged fuel lines leading to insufficient fuel supply and uneven cylinder operation, or transmission issues. Broken or burned high-voltage wires or spark plug failure causing a cylinder to misfire can also result in unstable engine operation and shaking. Check if the battery voltage is within the specified range. 2. Common Causes of Car Shaking: The most frequent causes of car shaking are a dirty throttle body or excessive carbon buildup in the fuel injectors. When there is too much carbon deposit inside the engine, the gasoline sprayed by the cold start injector is largely absorbed by the carbon, leading to an overly lean air-fuel mixture during cold starts and making ignition difficult. In such cases, the car may only start easily once the carbon deposits are saturated with gasoline. After starting, the gasoline adsorbed on the carbon deposits is drawn into the combustion chamber by the engine's vacuum, enriching the air-fuel mixture. This fluctuation between lean and rich mixtures causes unstable idle and shaking after a cold start.