This legislation aims to significantly alter the Environmental Protection Agency's (EPA) authority over vehicle emissions standards. It specifically repeals the EPA's final rule concerning multi-pollutant emissions standards for light-duty and medium-duty vehicles for model years 2027 and beyond, effectively nullifying that regulation. Furthermore, the bill amends the Clean Air Act to impose new restrictions on future tailpipe regulations. These amendments stipulate that the EPA cannot mandate the use of any specific technology or create regulations that would limit the availability of new motor vehicles based on their engine type. The Administrator of the EPA is also required to revise existing regulations within 24 months to ensure compliance with these new statutory limitations.