Tesla CEO Elon Musk acts in an "almost unethical" way, the outgoing CEO of the largest U.S. auto dealer chain told CNBC on Friday.

Musk recently said he expects Tesla to have all the features needed for fully self-driving cars by the end of the year. That seems like an almost impossible goal, Cox Automotive executive publisher Karl Brauer said Wednesday on CNBC's "The Exchange." Other companies working on autonomous driving technology, such as Waymo, are not making such bold predictions.

"I think he is overpromising on autonomous vehicles in an almost unethical way," AutoNation CEO Mike Jackson said on "Squawk Box," referring to Musk.

Jackson has long been a Tesla critic and has accused Musk of using "bait-and-switch" tactics on consumers, making commitments he cannot keep, and has said the electric car maker's business will not be sustainable over the long term.

In the interview Friday, Jackson once again criticized Tesla's practice of taking orders on the midsize Tesla Model 3 sedan, saying the cars Tesla has been building are different from the ones the company had said it planned to build. Tesla initially advertised its Model 3 at a price of $35,000 but has so far sold only more expensive versions.

"There's not another retailer in America that could get away with that bait and switch," Jackson said. Currently the cheapest Model 3 starts at $42,900. Musk has said that despite the originally advertised price, Tesla has had to prioritize the production of more expensive versions to keep margins high. At one point, Tesla had more than 400,000 reservations for the the Model 3.

Tesla has faced political and legal battles in several states over its decision to eschew the traditional dealership model in favor of a direct model that sells to customers.

AutoNation reported earnings of $1.10 on Friday, missing a consensus estimate by 4 cents. The dealership chain also said Jackson will end his long tenure in the top job in March, and Carl Liebert will succeed him on March 11. Liebert was formerly chief operating officer at financial services company USAA. He was also executive vice president of stores at home improvement retailer Home Depot.

AutoNation shares sank 6 percent in early trading Friday. Tesla's stock was up 1.2 percent.

"It was a challenging quarter, no question," Jackson said. New vehicle sales across the industry were down 10 percent in California, and environments in Texas and Florida were also problems.

"But even beyond those two explanations, I think retail automotive is getting more difficult," he said, attributing the challenges in part to the cyclical nature of the business.

Jackson said he expects a gradual downturn across the industry. He expects sales in 2019 to be about 16.8 million vehicles, down from 17.2 million in 2018.

Tesla did not immediately respond to CNBC's request for comment about Jackson's remarks.