Interesting Fuel Pressure Problem (please help)

I have been reading all the old posts about fuel pressure issues and could not find a solution to this problem I have. It is a 1990 SC no mods. It takes quite a bit of cranking to get it started. I have replaced the plugs, wires, and cam sensor so far. Once started, it seems to run pretty good except the idle is a little rough but it doesn't die. I did a fuel pressure check and here are my findings. I connected the gauge and there was no pressure. Turned the key on- still no pressure and did not hear the fuel pump. Cranked it over and the pressure built up to 30psi and then it started. The pressure stayed at a steady 30psi while idling. Then shut the engine off and the pressure went instantly back to zero. Any ideas on what this might be? What would cause the pump to not turn on when key is turned on? Also, why would the pressure drop so quickly after engine is shut off? Thanks in advance!

Joe

Sounds like a bad fuel regulator.

Coil pack was my igniton problem. Similar to what you described. I had changed everything in the system. Still haf the miss until i changed the coil.

Good afternoon

Suspect a bad fuel pump specifically a bad fuel pump check valve. I once changed a brand new fuel pump with the exact same fuel pressure problem. Started first with the fuel pressure regulator test. Pinched the return fuel line with pliers (had a rag wrapped around it) No fix. Next replace the fuel filter for suspect blockage. No fix. Each time fuel pressure gauge would instantly drop to zero after shut down. Changed the pump again. Fuel pressures test good. Return car to service.

Good luck.

Thank you for the responses! I suspected that it might be the fuel pump. What would you recommend I put in there? Stock or upgrade?

Joe