An era of Superman, because the mixture is too thick lead to idle instability.
     Customers into the factory repair: normal driving, in case of red light or traffic jams low-speed driving time is longer, there is idle instability, idling when the body has a jitter, the engine speed table small swing.
     Maintenance: demolition of the spark plug, black, for spark plug, idling normal, body jitter disappear, idle work for some time, the original failure again. The engine speed to 2000 rpm, work for 5 minutes or so, loose throttle into the idle state, idle and smooth work for some time, followed by idle instability. Once again check the spark plug, still black. Measuring oil pressure 420Kpa, too high, cleaning pressure regulator, oil pressure back to normal, and then idle work, after a long time failure did not appear. Once again check the spark plug, normal. After repeated visits to customers, this phenomenon did not appear again.