Chasing Hesitation/bog

[FixxerAuto]

Hello,
I have a 90 ZR1 that sat for about 3 years. Unfortunately, after start up, the car was drivable with a shaky idle and misfire/ lean backfire when hot. As well as a large hesitation when trying to use the secondaries.

So I replaced the fuel pumps with new Delphi pumps, replaced all the fuel injectors, plug wires, and coil packs. I checked and regapped the plugs but didn't really find any reason to replace them. I checked all of the vacuum components in the secondary system- replaced check valve. My vac pump no longer works, but it has never worked in the time Ive had the car... I found one fuel injector at 4 ohms and 4 others at 8 ohms which, i thought, was my problem.
Well, the idle is fixed and there is now no cough/ hesitation when i blip the throttle. And, until the car fully warms up, i can get some good full throttle, valet key on launches. But as soon as she fully warms up, I get a big bog when trying to accelerate wit the key on. Key off, everything is fine.
Fuel pressure is in spec when idling and bliping the throttle. But the pressure quickly drops to 0 when the engine is turned off. I wonder if the check valve is not holding on my secondary pump, causing an internal pressure leak when the pump shuts off? So, i run out of fuel before the secondary pump kicks back on at 3500rpm? Due to the loss of fuel volume through the failed check valve? Is it possible that my pressure regulator is allowing too much fuel to flow back to the tank to maintain pressure?

The car starts to accelerate and pushes me back in my seat, but i am quickly thrown forward against my seat belt. Any ideas?
Thanks