A group of Tesla investors is urging Elon Musk to commit at least 40 hours a week to running the electric vehicle company, arguing his undivided attention is needed to repair Tesla’s faltering sales and stock price volatility.

In a letter, some skeptical backers of the EV company have also asked its board to add a “new, truly independent” member and lay out a succession plan.

The Tesla boss said he was back to working "24/7" and that he needed to focus on his companies, including Tesla. The stock is up sharply since April lows.