Fuel Pressure Regulator
WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The fuel pressure regulator (2) is contained in the fuel pump module. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. The fuel pressure regulator is not vacuum based. Fuel pressure is controlled by a pressure balance across the regulator. The fuel system pressure is constant.