Fuel Pressure Regulator
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
Manufacturer does not provide testing procedures for many individual systems and components. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.1L CENTURY, GRAND PRIX & MALIBU article.