1. First, check whether the engine fixing bolts are too loose; 2. Check whether the engine output power is correct and whether the engine coolant meets the requirements;

3. Check whether the electrical and oil pipelines are fixed and reliable, and whether there is oil leakage or oil leakage;

4. Check whether the spark plug and ignition voltage divider are normal;

5. Check whether the engine timing is correct, adjust the engine oil and engine timing or replace the crankshaft belt;

6. Install the engine oil pan and check whether the rivets are loose;

7. Check whether the engine vibration gasket is installed correctly;

8. Check whether the connection between engine exhaust pipe and intake pipe is blocked.

9. Replace the air filter to make the air flow into the engine stably.

Million car purchase subsidy