What's wrong with the Big Dipper running only at 100 mph?

The main reasons are incorrect ignition advance angle, low fuel pressure, air leakage in intake system, fault of throttle position sensor or air flow meter, poor operation of injector and EGR system.

Second, the troubleshooting steps:

1. After starting the engine, does the "Check Engine" warning light go out?

2. 1 If the warning light does not go out, check the cause and location of the fault according to the fault code.

2.2 The warning light goes out, and check the oil pressure of the supply system, the working condition of the injector and the gasoline quality.

3. Check whether the ignition timing is delayed too much.

4. 1 Ignition timing is normal.

4.2 The ignition timing delay is too large. Check whether the knock sensor and ECU are normal.

5. Check whether the EGR system is normal.

6. Check whether the air intake and exhaust system is blocked.

7. Check whether the signals of air flow meter, throttle position sensor, crankshaft position sensor, camshaft position sensor and oxygen sensor are normal.

8. 1 is not normal, check the sensor fault.

8.2 Normal, check ignition high pressure and ignition energy when accelerating.

9. 1 If the ignition high voltage and ignition energy are abnormal, make fault diagnosis according to the ignition system.

9.2 Ignition high pressure and ignition energy are normal. Check ignition timing, cylinder pressure and engine mechanical failure.