ENGINE VIBRATION WHEN THE ENGINE STARTS AND GOES OFF WHEN THE AC ISTARTS

Hello, I'm surprised it is running based on the engine in the vehicle. There are a couple of sensors in the engine bay for both the 1.8t and 2.0t that allow water intrusion when washed from the top. Let the vehicle sit for a day or two, it will likely return to normal when it dries. In the future, wash the engine bay down with a low-pressure water hose to avoid this.