What Causes Engine Shaking During Acceleration?

[McMicah]

The reason for engine shaking during acceleration is the accumulation of carbon deposits in areas such as the throttle body, intake manifold, and valves. When the engine is cold, these deposits absorb some gasoline. Once the engine warms up, the gasoline evaporates, leading to an overly rich air-fuel mixture during idle, which causes unstable idle conditions. Therefore, car owners should not only inspect the throttle body and idle control valve but also check for excessive carbon deposits and dirt in the intake manifold. Excessive buildup can alter the cross-sectional area of the air passage, preventing the control unit from accurately regulating the idle air intake. This results in an overly rich or lean mixture, causing abnormal combustion and engine shaking. Additionally, it is important to check if the carbon canister is malfunctioning.