Scott Pruitt has only been head of the U.S. Environmental Protection Agency since Friday, but auto makers are wasting no time lobbying him. This week, the Alliance of Automobile Manufacturers wrote a letter to Pruitt asking him to withdraw passenger vehicle emissions rules put in place during the Obama administration.

The letter from Alliance CEO Mitch Bainwol said the EPA's vehicle emissions rules were "riddled with indefensible assumptions, inadequate analysis and a failure to engage with contrary evidence." Put in place in 2011 and finalized just last month, the rules require passenger vehicles to achieve an average fuel economy of 54.5 mpg by 2025.

General Motors, Toyota and Volkswagen are among the 12 auto makers represented by the Alliance, which contends the stricter fuel economy and emissions rules could result in the loss of 1 million jobs if consumers are unwilling to pay for more fuel efficient, and more expensive, vehicles.

Proponents of the emission curbs say they will, in fact, save billions of dollars, while improving air quality and limiting carbon emissions.

If the EPA does roll back the rules, it will set up a confrontation with California air quality regulators, who have put in place their own strict emissions standards and other plans to increase the number of zero-emissions vehicles.

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