Elon Musk unveiled Tesla Inc.’s highly anticipated self-driving taxi at a flashy event that was light on specifics, sending its stock sliding as investors questioned how the carmaker will achieve its ambitious goals.

Tesla’s stock price was down 8% early Friday after a Thursday event where company CEO Elon Musk unveiled a new two-door electric vehicle dubbed Cybercab that is designed for fully autonomous operation, a feature most notable in the car’s lack of steering wheel or pedals.

Tesla CEO Elon Musk first floated the idea of launching a robotaxi network using autonomous Teslas in 2019, saying he expected to begin deployment the following year. But Musk isn’t exactly known for sticking to his timelines.