Elon Musk has said that “excessive automation” is partly to blame for the serious backlog in production of Tesla cars, noting that human beings can in some situations do a better job. Mr Musk has come under fierce criticism for the delays facing his Model 3 sedan. “Yes, excessive automation at Tesla was a mistake,” he said. “To be precise, my mistake. Humans are underrated.” Caught in what Mr Musk has called “manufacturing hell”, the electric car firm has failed to hit its weekly production target of 2,500 Model 3 vehicles in the first quarter of 2018, fostering doubt within the industry that Tesla will be able to hit its 5,000-a-week target in three months time. “We had this crazy, complex network of conveyor belts. And it was not working, so we got rid of that whole thing," he said. "We got complacent about some of the things that we felt were our core technology. “We put too much new technology into the Model 3 all at once. This should have been staged." In February Elon Musk sent a red Tesla into space Credit: SpaceX Mr Musk, on a tour of the factory for CBS News, admitted that he sometimes slept at the factory when he was overwhelmed with work, and said the criticism was affecting him. "When things get really intense, I don't have time to go home and shower and change, so I just sleep here," the tech billionaire said. "Last time I was here, I actually slept literally on the floor, because the couch was too narrow." In the past month, Tesla has issued a voluntary recall of 123,000 of its older Model S vehicles, dealt with a fatal crash of a vehicle equipped with its semi-autonomous driving system and suffered a downgrade of its credit status. But Mr Musk said his immediate priority was solving production delays for the company's Model 3 sedan. "I'm definitely under stress, so if I seem like I'm not under stress then I'm going to be clear, I'm definitely under stress," he said.