What Causes Shaking During Acceleration?

[NatalieDella]

Here are the reasons for shaking during acceleration: 1. Clogged fuel system or dirty throttle body: Insufficient fuel supply at low throttle causes uneven cylinder operation leading to shaking. A dirty throttle body restricts air intake, causing uneven operation and vibration. 3. Faulty ignition wires: Broken or burnt ignition wires or spark plug failure in some cylinders result in unstable engine operation and shaking. When excessive carbon deposits accumulate inside the engine, the fuel injected by cold-start injectors gets largely absorbed by these deposits, creating an over-lean mixture that makes starting difficult. In this situation, the engine only starts easily after the carbon deposits become saturated with fuel. After starting, the fuel adsorbed on carbon deposits gets drawn into the cylinders by engine vacuum, enriching the mixture. This alternation between lean and rich air-fuel mixtures causes idle shaking after cold starts.