The mileage is about 127 thousand km, carrying the manual transmission of the FAW Pentium B70 2. 3L car in 2008. User response: when the vehicle is sliding on the neutral side, the vehicle suddenly stalls, and the engine is restarted without idle speed, so that the engine can not maintain normal operation. Fault diagnosis: first, connect the fault diagnosis instrument to detect, do not find fault code. Using fault diagnosis instrument to observe dynamic data flow, it is found that both long and short term fuel correction values are too large. The long-term fuel correction value is 36% and the short-term fuel correction value is 38%. The general cause of this fault is the problem of fuel system, the air leakage of the intake system, or some of the sensors that control the amount of fuel injection (such as air flow meter, air inlet pressure sensor, etc.). In the process of inspection, it is also found that in the moment of starting the engine, the front of the engine has air leakage, but it is normal to check the solenoid valve and pipeline outside the intake system. When the vehicle is lifted and checked, it is observed that a hose with a crankcase on the inside of the intake manifold falls off, causing the air leakage of the intake pipe serious, causing the engine to be unable to maintain normal operation. Troubleshooting: re install the crankcase ventilation hose and tighten it up after trial run, troubleshooting. Failure summary: because extra air is measured in the engine combustor without air flow meter, the mixture is sparse. It should be noted that the 2. 0L and 2.3L engines are different in the intake system. The 2. 0L engine has no ventilation pipe.