车型:E90,配置N52发动机。行驶里程:91798km。故障现象:客户反映在冷车或者等红灯时发动机偶尔熄火,没有检查控制信息,也没有任何故障灯点亮,但重新启动后一切正常。故障诊断:首先同客户一起验证故障现象,试车10km,始终无法试出故障,但是等红灯时发动机偶尔会出现一两次转速上下波动100r/min左右的现象。询问客户,此故障已经出现了3个月了,熄火频率有越来越高的趋势,客户之前已经尝试更换了不 Model: E90, equipped with N52 engine. Mileage: 91798km. Symptom: The customer reflected in the cold car or other red lights occasionally turn off the engine, did not check the control information, there is no fault light is lit, but after restarting everything is normal. Fault diagnosis: First, together with the customer to verify the fault phenomenon, test 10km, always failed to try out the fault, but the red light when the engine appears once or twice the speed fluctuation up and down 100r / min or so phenomenon. Ask the customer, this fault has been appeared for 3 months, the flameout frequency is getting higher and higher, the customer has tried to replace before