Elon Musk has done a great job pitching Tesla (TSLA) - Get Report to the masses, but there are some problems says one industry titan.

"We still don't have a viable economic model for delivering an electric car," Fiat Chrysler (FCAU) - Get Report CEO Sergio Marchionne told a group of reporters at an event on Monday. "As much as I like Elon Musk, and he's a good friend and actually he's done a phenomenal job of marketing Telsa, I remain unconvinced of a ... economic viability of the model that he's pitching."

To Marchionne, the costs of producing an electric car need to come down in order to make them viable. If one can't get the costs down, then Marchionne believes automakers must develop cars that can use both gas and electric for power.

Production delays will only add to Tesla's bloated costs, and likely keep profits a mere mirage off into the distance.

Tesla reported earlier in October that it produced just 220 Model 3s in the third quarter, well below Wall Street expectations of 1,260 according to FactSet. Tesla attributed the miss to "production bottlenecks" and told investors that "there are no fundamental issues with the Model 3 production or supply chain," in a statement.

On Friday afternoon, Musk used more colorful language when he tweeted that the company is "deep in production hell." He added that Tesla would delay the unveiling of Tesla's new semi vehicle as it focuses attention on the Model 3 and supplying batteries to Puerto Rico.

Chris Nolter contributed to this story.

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