The pressure regulator, used on 2001 and 2002 Acura and 2003 and 2004 Honda models, is located on a junction block at the left end of the engine. To replace it, first relieve the system fuel pressure. Next, disconnect the cable from the negative battery terminal. Remove the engine cover and disconnect the vacuum hose from the fuel pressure regulator. Squeeze the clamp on the fuel return hose and slide it back, then detach the fuel return hose from the pressure regulator. Be prepared for some fuel to spill out. Unscrew the fuel pressure regulator from the junction block. Be sure to use a new 0-ring when installing the new pressure regulator. Even if you're planning to reinstall the old pressure regulator, discard the old O-ring, then install a new O-ring and coat it with a little clean engine oil. Make sure that you don't damage the new O-ring during installation or reassembly, or it might leak when subjected to operating fuel pressure. When installing the fuel pressure regulator, screw it in by hand until it stops, then turn it counterclockwise until it is properly oriented. Orient the regulator so that the vacuum hose pipe is facing straight back (toward the firewall). Installation is otherwise the reverse of removal. Be sure to tighten the fuel pressure regulator locking nut. When you're done, reconnect the cable to the negative battery terminal, then start the engine and check for fuel leaks around the fuel pressure regulator.