Cadillac Repair: 98 Deville Northstar, oil pressure switch, fuel pump relay

Question
QUESTION: car starts but SOMETIMES it takes 3 tries of cranking {about-3sec intervals] before it starts. It does prime when ignition is turned to run pos. I checked the psi reg and doesn't appear to be leaking. Fuel psi is 42 with line on and 52 with vac line off. I cant get it to go into condition when troubleshooting and temp doesn't seam to make a differance.Does it have to see oil psi before is starts? Please help, Don't want to eat a starter.
Thanks

ANSWER: IS or HAS the check engine light ever illuminated on the dash while driving the vehicle ?.

After the car does start, does it run as it should ?.

---------- FOLLOW-UP ----------

QUESTION: NO, the check eng light has never come on and there are no codes stored. The car runs as it should but when it does start after the problem it stumbles for just a sec or so, but again no codes or light.

Answer
As soon as you turn ON the ignition switch to start the engine a 2 second ONLY battery voltage signal is sent from the computer to the fuel pump relay and from the relay back to the fuel pump in the fuel tank. This runs the fuel pump for ONLY 2 seconds of which pressurizes the fuel system in preparation to start the engine.

Once the engine starts, The computer BYPASSES the fuel pump relay and  sends constant contionous battery voltage from the computer to the oil pressure switch of which is now CLOSED because the oil pressure is UP because the engine is running. Therefore the battery voltage flows thru the oil pressure switch back to the fuel pump to run the fuel pump constantly until you turn OFF the engine. If the oil pressure light remains ON after the car starts the most likely suspect would be to replace the oil pressure switch,.