Dandy74

Ok so here is my concern i have been dealing with this car for a week lol but what I'm seeing is i have a p624 code in the pcm. The epc pressure is bouncing from 24psi to 124 psi at idle. The vehicle will idle fine at times and when you step into it it acts like the fuel pump is gone pops no power. I pulled up some pids and in r n d 1 it will actup and it will pop into open loop and both 02's will drop to 0v and it just goes dead lean i was reading that there is 2 limp modes one where it would supply known good voltages back to the pcm then hardware losWill the Hardware limited operating strategy cause this concern? Now the weird part as soon as i select 2nd gear the engine wakes up and responds anyone have any input?