The idling jitter and acceleration of 4g69 engine are very weak. The throttle body, spark plug, high voltage coil and ECU have all been replaced, and the timing has also been checked. Why?

I'm sure it can be solved. Generally speaking, engine idle jitter is caused by the poor working of one or more cylinders of the engine, and another reason is that the engine idle speed is too low. The second reason can be ruled out according to the parts you replace. So I suggest you measure the cylinder pressure of each cylinder of the engine. If the pressure of one or more cylinders does not reach the normal value, it means that one or more cylinders are not working properly.