Warning: See warning in subsection 1.
1. Relieve the pressure in the fuel system (see subsection 2).
2. Disconnect the negative battery cable.
3. Remove the intake air duct resonator (see subsection 9).
4. Clean the areas around the fuel pressure regulator and fuel lines.
5. Disconnect the regulator vacuum line and disconnect the engine wiring harness from the front of the engine (see illustration).
13.5. Elements of the fuel pressure regulator: A. Vacuum line; B. Fuel drain line; C. Fastening screw
6. Disconnect the fuel return line (see subsection 4) and remove the holder.
7. Unscrew the mounting screw and remove the fuel pressure regulator.
Caution: Wrap a cloth around the regulator to absorb any fuel that may spill when removing it.
8. Install a new sealing ring and lubricate it with clean engine oil (see illustration).
13.8. Lubricate the sealing ring with a thin layer of engine oil
9. The rest of the installation procedure is carried out in the reverse order of removal.
10. Tighten the fuel pressure regulator screw to the specified torque.
(Information taken from the official website CHEVYMAN.RU)