Modern famous air conditioners can obviously feel shaking when they are turned on to the fifth gear, so it's okay. What's going on here?

The most common fault points of vehicle vibration with air conditioning: First, the throttle may be too dirty. Because the air conditioner is turned on, the air conditioning pump works and the engine load increases, it is necessary to increase the throttle opening and stabilize the engine. However, if the throttle is too dirty, too much carbon deposit on the valve plate will lead to improper throttle opening, so the vehicle will feel jitter. The second possibility is that the rubber parts inside the engine bracket are aging and cracked. Because this part can absorb the vibration when the engine is working. If the rubber parts crack, it will not play this role, and the engine jitter will be transmitted to the cab, so it will feel jitter. You can check these two parts first.