This bill seeks to prohibit the enforcement of federal laws requiring the installation, certification, or maintenance of emissions control devices and onboard diagnostic systems on motor vehicles and engines. It explicitly removes the Environmental Protection Agency's authority to promulgate or enforce such requirements under the Clean Air Act or any other federal law. The legislation further eliminates civil or criminal liability for the manufacture, sale, use, or modification of vehicles or engines without these devices. Additionally, it mandates the repeal of all related federal regulations and requires the vacatur of past criminal penalties of imprisonment, along with the expungement of associated records for civil or criminal liability.