Symptom:
    After the cool car is started, the exhaust pipe is unstable and the engine jitter is longer.
    Check analysis:
    The engine control unit to maintain normal combustion and stable idling, no λ adjustment, the injector fuel injection is large, the mixture is thick, the mixture combustion is not complete, the exhaust emissions of pollutants serious. To this end in the Polaris 1.8 and 1.8T sedan installed on the secondary air jet device, its role is to reduce the cold start when the exhaust pollution. In the warm-up phase, the secondary air injection device injects fresh air into the exhaust pipe of the engine so that the combustible components in the exhaust gas continue to burn to reduce the emission of pollutants to Euro III emission standards. The time of secondary air injection depends on the temperature of the coolant, and the maximum time does not exceed 100 s. In the secondary air jet, the exhaust pipe exhausted instability, but the instability will not exceed 100s, the summer instability time is shorter, the winter instability time longer, but all belong to the normal situation. If the exhaust is unstable and the engine jitter longer, may be valve, valve seat and combustion chamber caused by excessive carbon deposition, which requires cleaning Coke. But the first step is to check the fault code and read the data stream, if there are problems should be excluded, followed by other diagnostic or troubleshooting, such as cleaning coke (bottle) and fuel system free cleaning.
    Troubleshooting: the use of fault diagnosis instrument V.A.G1551 query no memory fault code, data flow are normal. And then the car for coke and fuel system free cleaning, the warmer stage of the trial exhaust pipe exhaust when the unstable time to shorten the warm idle fast jitter phenomenon improved significantly.