A stressed Elon Musk says his electric vehicle car company Tesla is going to deliver all the Model 3 cars people have ordered, if six to nine months behind schedule.

He also takes responsibility for the delay and a series of missed targets.

"You started saying, 'We'll do 5,000 a week.' Then, okay, that didn't work out, 'We'll do 2,500 a week.' And now it's a little over 2,000 a week," says Gayle King, host of "CBS This Morning," during an interview with Elon Musk at the Tesla factory in Fremont, California, which aired Friday.

"Does that trouble you?" she asks.

"Yeah. No, that's true…. I need to figure out how to be better…. And then we can be better at meeting goals," Musk says.

Part of the problem, says Musk, is that Tesla was trying to do too much at once.

"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 — this should have been staged," he says.

Building a Model 3 electric car also requires sophisticated factory technology.

"In some cases, the robots actually slowed the production. Right?" King asks.

"Yes, they did….We had this crazy, complex network of conveyor belts….And it was not working, so we got rid of that whole thing," Musk says.

Yes, excessive automation at Tesla was a mistake. To be precise, my mistake. Humans are underrated.

Musk calls the situation "production hell," even "worse than I thought," but tells King its getting on track.

"I'm feeling pretty optimistic about where Tesla is at this point," he says. "At this point I can have a clear understanding of the path out of hell, and I did not, until recently, have a clear understanding.

"We'll probably have, I don't know, a three- or four-fold increase in Model 3 output in the second quarter," he adds.

Missing Model 3 production targets isn't the only challenge facing Tesla. It has also been dealing with the fallout of a recall of 123,000 older Model 3 vehicles, a fatal crash of a Tesla with its autopilot systems engaged, a downgrade of its credit by ratings agency Moody's in March and a Goldman Sachs analyst who cut a 12-month price target on Tesla stock.