用一辆CA141大货车进行驾驶训练时，行驶不到5km，就发现发动机低速工作不稳，好象有个别缸木工作。起步时要么熄火，要么严重闯动，训练无法进行，只好停车检查发动机。首先查看化油器，浮子室油面高度正常，估计油路有故障的可能性不大。接着检查电路，逐缸试火发现第三缸工? Driving with a CA141 large truck driving training, less than 5km, we found that the engine working at low speed instability, as if a few cylinder work. Start off or turn off, or a serious break in, training can not be conducted, had to stop checking the engine. First check the carburetor, the normal height of the surface of the float chamber, it is estimated that the possibility of faulty oil is not. Then check the circuit, cylinder test fire found the third cylinder workers?