A Subaru Milo 2.5 car carrying a CVT transmission on a mileage of about 100 thousand km in 2010. User response: when the speed of the vehicle reaches 100 km/h, it will be very difficult to continue to speed up. At this point, the engine speed is very high, sometimes it can reach 5000 r/min, but the speed is very slow. At the same time, the power performance at low speed is also significantly reduced. Before overtaking or speeding up, the accelerator pedal is a little bit faster, and the power is immediately delivered. Not now. Overtaking or speeding up can only be done by stepping the accelerator pedal to the bottom. Replacing gasoline in other 4S shops, cleaning fuel injectors and carbon deposition inside the cylinders did not solve the problem. Another phenomenon is that the fault light has not been lit. Inspection and analysis: first of all, with the customer test, it is found that when the speed reaches 100 km/h, then the speed of the accelerator pedal is 5000 r/min, but the speed of the car is not very fast. Although it is also able to reach 150 km/h, normal motor vehicles should increase engine speed and vehicle speed, especially this CVT model. But the speed of the car is out of proportion to the speed of the engine. The engine speed is very high and the speed is not very fast. At the beginning of acceleration, the accelerator pedal can be reached to 5000 r/min, but the speed is not very fast. Check with the tester, there is no fault code, and there is nothing unusual about the data. A change of air flow meter, the fault has not been solved, consider whether the exhaust pipe is blocked, but another engine speed can reach 5000 r/min, the exhaust pipe should not be blocked. Is it slippery in the transmission? So another stall experiment was made, and the engine speed was 2700 r/min, which was also normal. It shows that the transmission has no problem, not skidding. The feeling of driving is like the lack of cylinder pressure and the feeling that the engine is idle. The stall test proves that the engine is working properly. I looked at the data again, but I didn't notice anything unusual. But judging from experience, it seems that the ignition energy is insufficient. Think of it here and decide to replace the 4 ignition coils. Troubleshooting: after changing the ignition coil and going out for trial run, it feels different at once. If the accelerator pedal is slightly lighter, the car will accelerate and the power will surge. It shows that the cause of the trouble is found, because the ignition energy of the ignition coil is insufficient, and the fault is replaced after replacement.