Why does the engine shake in neutral gear?

[IvanDella]

Car engine shaking in neutral gear can be caused by the following reasons: 1. Poor quality gasoline: This usually occurs when low-quality gasoline is added at non-standard gas stations, resulting in incomplete combustion of the air-fuel mixture during engine operation and triggering the engine warning light. While this doesn't affect driving safety, it may cause some degree of damage to the engine. 2. Oxygen sensor failure: Modern vehicles are equipped with two oxygen sensors, one before and one after the three-way catalytic converter. The front oxygen sensor detects the air-fuel ratio under different engine operating conditions, and the ECU adjusts fuel injection and calculates ignition timing based on this signal. The rear sensor mainly monitors the performance of the three-way catalytic converter. Therefore, if the oxygen sensor is damaged or the sensor connector is damaged or loose, it may cause the air-fuel mixture to become too lean or too rich, triggering the warning light.