Dongfeng xiaokang v29 engine has no idle speed and uneven acceleration. What's wrong with stepping on the gas pedal?

Because the valve clearance is too small, the valve leaks, resulting in insufficient cylinder pressure and high intake pressure. It seems that the cylinder head can only be removed. The cylinder head of this car is the same as that of the Toyota engine. It uses an intake camshaft with scissors, and there are two gears on the gear of the intake camshaft. When removing the camshaft, screw a 6mm screw on the maintenance hole to lock the main gear and the auxiliary gear (as shown in figure 1), then align the marks on the gears of the intake camshaft and the exhaust camshaft, and then remove the intake camshaft and the exhaust camshaft. The cylinder head has been removed. Then mark the tappets, arrange them in order, press the valves, and then look at the valves and valves. The valve of each cylinder has different degrees of air leakage. However, the car only traveled more than 54,000 kilometers. It's a new car just bought this year, and the valve can be reused. Looking at the valve opening, the width of the working face exceeds 1mm, and the valve opening of the exhaust valve is almost stuck in the cylinder head. The reason why the valve clearance is too small is that the valve port sinks (as shown in Figure 2), and the valve sinks into the valve port, resulting in too small or even no clearance between the valve lifter and the camshaft. It is suggested to replace the valve port, and you can buy the valve port of Chang 'an Star CB 10 engine. Both Dongfeng Xiaokang and Chang 'an Star are mini cars, and the accessories should be universal, so they decided to replace the valves.