Tesla Inc has temporarily suspended its Model 3 assembly line in what the company said on Monday was a planned production pause, as the automaker continues to face challenges ramping up its new sedan.It was the second time since February that Tesla has temporarily shut down its production line for the Model 3 at its Fremont, California plant."These periods are used to improve automation and systematically address bottlenecks in order to increase production rates," a Tesla representative said on Monday. BuzzFeed, which first reported the news, said workers were expected to use vacation days or stay home without pay during the four- to five-day production pause.After repeated delays in production of its Model 3 sedan, Tesla is now trying to catch up to a target of building 2,500 vehicles per week by the end of the second quarter. Problems within its heavily roboticized assembly line have complicated those efforts.