RPMs fall when I floor the throttle pedal

[Xayne]

Hi, I'm new here and I'm fixing up 98 Mustang and needed some help with troubleshooting throttle response issue when I go around 3K on acceleration. Also the car will randomly run rough at idle and just die. But will start right back up just fine. I have been playing around with Fordscan and here is a data capture of the problem. Not sure what I need to look at and trying to avoid throwing money at good parts.

 

[Noobz347]

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?

 

[Xayne]

Stock EEC. I now have a code P0174-C. I have hooked up fuel pressure gage and the pressure drops to 10 psi and the surging starts to happen. Let off the gas and the PSI goes back up to 35. I'm now on fuel pump #3 and still having the same issue. The gas tank is clean and fuel filter has been replaced twice now. Are these fuel pumps junk these days?

 

[Noobz347]

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.