(May 29): Delivery for Tesla Inc.’s Model S Plaid will be pushed back a week to June 10, CEO Elon Musk said in a tweet.

The car “needs one more week of tweak,” Musk said in explaining the delay.

The Model S Plaid, the automaker’s quickest electric vehicle to date, was scheduled to be unveiled at a June 4 delivery event for customers at its factory in Fremont, California.