RPMs fall when I floor the throttle pedal

Well, you lost me with the foreskin

Anyway,
Is this an unaltered EEC?
are there codes present?
what is fuel pressure?
What is input voltage at the coil and at the fuel pump relay when this occurs?

Check the vacuum hose running to the regulator. See if it smells like gas.

Next, make sure you're getting vacuum to that line and check to see where it's routed. It should be routed as directly as possible to either the manifold or firewall vac tree.

With 3 pumps under your belt, I'll assume that it's not the issue. Now, we have to determine why your fuel pressure is dropping off. You should prepare to get voltage readings from the wires between the fuel pump relay and pump when this occurs.