Flush the engine compartment with water. If the throttle is higher, the car will shake after a while. Could it be that the timing belt slipped

The timing belt is covered and cannot be seen at all. The timing belt will not slip. If it slips, the valve mechanism and valve will be completely finished.

The belt you see is the belt that is responsible for the operation of the water pump and generator, and may also be equipped with the electromagnetic clutch of the air conditioner.

When I started the engine for the first time after cleaning, it was a little shaky. There may be moisture or moisture, which interferes with the ignition circuit of the engine and has a short circuit, which reduces the voltage and affects the normal operation of a cylinder. But after a while, the engine became hot, the water evaporated, the voltage was right, the cylinders worked normally and the engine stopped shaking.