问：粗糙的闲置，低齿轮的电源，犹豫不决，P0300，P0420和P0455代码的气体里程非常差

嗨，这些代码很可能彼此相关，并导致代码P0300结果的失火。代码P0420与催化剂系统效率低下有关，这通常是原因催化转化器失败或一个氧传感器故障。代码P0455与EVAP系统泄漏有关，这意味着通风孔控制阀可能会损坏或无法正常工作。您的汽车有一个小的清除阀吹扫螺线管在蒸发排放系统中，当这些烟雾在内部积聚时，可以控制燃料箱中的烟气，尤其是当您用汽油加油时。蒸发系统可防止燃油箱从燃油箱中逃脱到大气中。蒸发系统收集并暂时将燃油蒸气存储在木炭罐中。木炭罐中充满活性碳颗粒，可吸收燃料蒸气。发动机运行时，将燃油蒸气从罐中清除并在发动机中燃烧。排气控制阀（电磁阀）控制木炭罐中外部空气的流动。通风阀由发动机计算机（PCM）控制。通常，通风阀是打开的。当发动机计算机测试EVAP系统是否泄漏时，它关闭。如果检测到EVAP系统的泄漏，则检查引擎灯将在破折号上照亮，并且与问题有关的故障代码将存储在发动机计算机中。 When an air leak is present in the EVAP system, the MAP sensor will not be able to determine the air density, and the MAF sensor will not be able to determine the volume of air, entering the engine correctly. This will lead to an over fueling situation or an under fueling situation depending on the size of the air leak and engine operating speeds and load. This may eventually lead to catalytic converter problems as well as misfiring problems. I would recommend having an expert from Your Mechanic come to your location to diagnose and inspect your vehicle.