Fuel pressure

I have a 1998 ford escort lx 2.0 sohc with 57,212 miles with and auto trans. Everytime I start the car it seems to crank awhile and then starts. I went and changed the fuel filter and same thing so I checked the fuel pressure and it was zero when I turned the key on the pressure goes to 34psi and with the engine running it has 36psi at idle as soon as I shut the car off the pressure drops to zero. I checked a couple of books and I am getting different pressures for this car some say 36 to 40 psi and others says 55 to 85 psi. Now I am some what sure I asked a couple of friend mechs and they say the pressure should hold so everytime the car restarts it doesn't have to build pressure in the system for a easy restart. But nobody can give me the exact answer if the pump should hold pressure what is the pressure?
Any help please.