The car is a 93 integra with a obd1 gsr swap in there. It has an aem fuel rail with gauge and the pressure regulator. The car would start, run, then all of the sudden it'll lose fuel pressure and die after awhile. If I unplug the battery and plug it back in, the fuel pump would prime and it would be good to go again. What could be the problem? Main relay? hoepfully?

 

Could be the fuel filter, or the relay like you said.

 

If it sometimes doesn't prime but you're turning the key forward, it's the main relay. Mine has been weird this summer from the heat