Fuel Pressure Regulator
WARNING: This page is about a different car, the 1996 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
Fuel pressure regulator is a vacuum-controlled diaphragm type, which uses manifold vacuum to modify fuel pressure to compensate for engine load fuel requirements. Connect fuel pressure gauge to fuel pressure service port. Start engine and note fuel pressure. Disconnect vacuum hose from fuel pressure regulator. Fuel pressure should increase 4-10 psi (.28-.70 kg/cm2 ). If pressure does not increase 4-10 psi (.28-.70 kg/cm2 ), check for presence of manifold vacuum at signal line. If vacuum is not present, check for kinked, cut or split vacuum hose or plugged throttle body vacuum port. If vacuum is present and no pressure change occurs, replace fuel pressure regulator.