What Causes Engine Shaking at Idle and Lack of Power During Acceleration?

[DeArcher]

The primary cause of this issue is the accumulation of carbon deposits in components such as the throttle body, intake manifold, and valves. When the engine is cold, these deposits absorb some gasoline. As the engine warms up, the gasoline evaporates, leading to an overly rich air-fuel mixture during idle, which results in unstable idle conditions. Below is a detailed explanation: If the three-way catalytic converter is clogged, it will directly affect the vehicle's acceleration performance and also increase fuel consumption, causing a noticeable lack of power during acceleration. Therefore, it's essential not only to inspect the throttle body and idle control valve but also to check for excessive carbon buildup and dirt in the intake manifold. Excessive deposits can alter the cross-sectional area of the air passage, preventing the engine control unit from precisely regulating the idle air intake. This can result in an air-fuel mixture that is either too rich or too lean, leading to abnormal combustion and engine shaking. Additionally, it's important to inspect the carbon canister for any potential malfunctions.