Under what circumstances should the throttle assembly of Changhe Freda be replaced?

The work to be done before replacing the throttle valve is: 1: measure whether the cylinder pressure of each cylinder is uniform; 2. Adjust the ignition timing to the factory specified value; 3. Clean and check the atomization of the four nozzles; 4. Eliminate possible faults of ignition system (cylinder pipeline, spark plug, ignition coil, etc.). ); 5. Read whether there is a fault code and the operation of each sensor with decoded gas. ...