What Causes Engine Shaking in Classic Focus?

[SanJanelle]

The causes of engine shaking in Classic Focus are as follows: 1. Engine intake pipe leakage: The intake system contains many intake manifolds or various valves, and any leakage can allow unintended gases to enter, resulting in excessively high or low concentration of the air-fuel mixture in the intake manifold, ultimately causing intermittent engine shaking or weak idle symptoms. 2. Fuel system blockage or malfunction: Due to a blocked fuel tank vent, clogged fuel tank switch, fuel filter, or fuel lines between the fuel tank and carburetor, the engine may not receive the required amount of fuel during idle, leading to a lean air-fuel mixture, weakened engine power output, and idle shaking.