The fuel pressure regulator is located at the firewall end of the driver's side fuel rail. It somewhat resembles a round hat with a brim and will have a hose running straight down into it.

The FSM states:
If the fuel pressure is high, replace the fuel pressure regulator.
If the fuel pressure is low, check these parts:
- fuel hoses and connections
- fuel pump
- fuel filter
- fuel pressure regulator
- vacuum switching valve for fuel pressure control

It recommends removing the bolt in the driver's side fuel rail (in the front of engine) and connecting a fuel pressure gauge to check the fuel pressure at idle and after the engine is turned off.

It seems that the fuel pump may be getting weak after 10 years. I may hook up a fuel pressure gauge at work before I drop the tank and replace the fuel pump and sending unit.