Vibrating when accelerating into 3rd gear. Car vibrates up and down and steering

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. So sorry to hear you're having trouble with your Impala. Vibrations when accelerating, especially in 3rd gear, can be a bit unsettling. A couple of likely culprits would be an imbalanced part in the drivetrain or a failing torque converter. Since the vibration eases when you let off the gas, it's likely related to something under load. Given that you just bought the car, getting this checked out and addressed is a good idea so it doesn't lead to other problems down the road. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!