Search for a thread started by me: "'Fuel Accumulator Failure Analysis". You don't need a pressure gage. There is a simple test you can perform on the car to determine if the accumulator has a leaky internal diaphragm that shorts fuel back into the tank to pump feed hose.

If the diaphragm leaks, fuel pressure will rapidly bleed off after engine shutdown, and it will take considerable cranking to build pressure for the next restart. This can happen hot or cold, and it can be an intermittent problem, but will become more frequent with continued use.

Many FPRs get replaced when the real problem is the accumulator. AFAIK know the FPR has no organic internal parts, but the accumulator does, which are subject to both deterioration with time and cracks due to repeated stress. You can clearly see the cranks in the photos I posted in the above referenced post that caused the internal leak.

With the new accumulator, my car immediately returned to normally quick cold and hot starts, and it's easy to change.

Duke