Tesla's First-Quarter Deliveries Slump on Musk Backlash, Weak Demand Reuters $Tesla Motors(TSLA)$ April 2 (Reuters) - Tesla's first-quarter deliveries fell 13%, hurt by backlash against CEO Elon Musk's political stance, rising competition and its aging line up of electric vehicles, sending its shares down more than 5% in morning trading. It delivered 336,681 vehicles in the first quarter, down from 386,810 units a year ago. Tesla was expected to report about 372,410 vehicles, according to an average estimate of 15 analysts from Visible Alpha. The electric automaker's stumbling sales indicate that the one-time leading brand is reeling from the fallout of the company not refreshing its vehicle lineup in years an