What are the reasons for idle vibration in the new Excelle 1.5?

[AmyMarie]

The reasons for idle vibration in the new Excelle 1.5 include: poor fuel combustion, insufficient ignition energy due to spark plug failure, air intake system leakage or low fuel pressure, poor injector atomization, improper idle adjustment, malfunctioning idle control valve or bypass air valve, carbon deposits on valves and intake ports, etc. Below is an analysis of these causes: 1. Intake manifold or various valve leaks, when air, gasoline vapor, or combustion exhaust that should not enter the intake manifold causes the mixture to be too rich or too lean, leading to abnormal engine combustion. When the leakage affects only individual cylinders, the engine will experience more severe vibration, especially impacting cold idle conditions. 2. Excessive carbon deposits and dirt on the throttle body and surrounding intake ports change the cross-sectional area of the air passage, preventing the control unit from precisely controlling the idle air intake. This results in a mixture that is too rich or too lean, causing abnormal combustion and engine vibration.