A South East V3 rhombus car with a 4A91 mileage of about 60 thousand km, with a mileage of about 4A91. Users reflect the car's acceleration. Inspection and analysis: maintenance personnel test run, found that when the car at medium speed, even if the accelerator pedal to the bottom, the vehicle also has no obvious acceleration feeling. Check the engine control unit, no fault code. Measurement of fuel pressure, no abnormal. Check the spark plugs to jump fire, normal. After cleaning the injector to test the car, the failure is still. Connecting the fault diagnosis instrument road test, it is found that when the vehicle runs 4 gears and the speed reaches 50 km/h, the accelerator pedal is suddenly stepped on to the end. At this time the intake volume can reach 52 g/s, but the speed increases extremely slowly. For such a high intake volume, the output torque of the engine is obviously too low, which indicates that the energy released by the mixture combustion is insufficient. It can be seen from the correction of fuel injection that the combustion of the mixture is sufficient, which eliminates the possibility of insufficient power due to the poor combustion of the mixture. From the point of view of air flow, the intake volume of the engine is sufficient. It should be said that the torque output should not be too low, but the actual situation is not. The fuel samples taken from the fuel tank were compared with the normal fuel, and the difference was quite different. Using normal fuel for road test, it is found that the performance of the vehicle is normal, and the fault is judged by fuel quality. Troubleshooting: thoroughly replace the fuel and clean the fuel supply system, then confirm the trouble shooting.