DI, 1997, 148K.
I have been having problems with starting my DI. (It always start and sometimes start right on) The fuel pump still works but the pressure is low and I have to get under the fuel tank to hear it while before it was clearly heard from the driver seat. I just replaced the fuel filter and I am waiting for the fuel pump. But what I just want is to share a curiosity, or at least it is hard for me to understand. I turn the key to II position and the fuel pressure is only 20 psi. I turn the key back and pull it off, and the fuel pressure starts slowly rising all the way to 38 psi, it takes about three minutes to get there, then slowly starts going down to almost zero in about 10 minutes. What goes on? Again, this is all without turning on engine. By the way, the pressure with the engine running is only 24-26 psi, so I assume the pump is just worn out and cannot rise to +30psi, though somehow it does get to 38 when nothing is running *go figure*

 

Your pump sound like it is getting tired, especially with your miloeage.
The pump is regulated by the ECU so it only stays on long enough, abot 4 to 5 seconds, to prime the engine, then it goes off if the engine is not started. That being the case, your testing procedure is probably very accurate.
As for bleeding down, there is a valve on the pump that when old will allow this to happen, the new pump will come with a new valve.
Now it hasn't been mentioned, but you may have an issue with your fuel pressure regulator that may be a factor in this also.

 

Thanks Mike. In another post I talked about my whole diagnosing chain. You are right, the regulator is on the scope. I will replace the pump first, since with the mileage on it there is not much more to hope from it. Then I will see if the regulator need replacing. The fuel pump now is cheaper than I though, about $220 from Atlantic. Mine is the non AEL 1997.