To amend section 203(a) of the Clean Air Act to permit the conversion of a motor vehicle for the use of natural gas fuel, and for other purposes.

Amends the Clean Air Act to provide an exemption to the prohibition against removing or rendering inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with such Act with respect to an action for the purpose of converting a motor vehicle to use natural gas fuel.