If it's not the lane departure warning which you can check in the car settings then I'd bet you've got a wheel or two that has lost some wheel weights. It's easy to check, just look on the inside of the wheels (yes all four) and look for the little square/rectangle weights, you'll notice if one isn't with his friends anymore as there will be an empty spot or two and a bunch of glue/adhesive. If that's what it is, just take it to your favorite local tire/wheel shop and have it rebalanced or schedule with Tesla but that could take awhile.