To answer your question NOPE.

If you look at Adrian other PDF file the engine is at 700 rpm but the voltage is 16.

https://www.dropbox.com/s/yf5jm56z0k...20Loader_1.pdf

i see consistent references to fuel relay, which is the only before engine fuel related thing, and the oil level sensor, which was mentioned somewhere in the depth of this thread, could have had similar effect on the symptoms... the cats and the lean conditions can be secondary to the fuel issues...

Adrian, when you pulled the glove compartment, and looked at the area, did you replace the relay, or just wiggled it? even though i was with this thread from the very beginning, but at my advanced age, some of my memory functions are not as advanced any longer... :) a suggestion about a chaffed or nicked wire still may stand valid, as that type of problem would be intermittent to consistent without any logic...

at this point it is clear that your fuel pump, being brand new, is not the main culprit... the passive pump on the other side of the tank probably has nothing to do with your problem, as it only transfers fuel from one side to another and does not build actual pressure in the system, since it is only passive device...

from hydraulics point of view, a pressure applied on one end of the system should transfer to the other end of the system unimpeded, unless that pressure is somehow regulated - the regulating can happen, if the transfer line is "valved", if the liquid is compressed and somehow did not transfer the pressure (even though, the mere fact of compressed liquid means, it is under pressure), there is a hole and the pressure is siphoning out, there is an obstruction in the line...

it seems that the pump is producing the pressure needed... the pressure is at the fuel filter... then internally it is applied to the fuel pressure regualtor, which should stabilize the pressure through whatever techniques used, and the pressure at the outlet of the regulator should be somewhat constant, or steady... then, that pressure is transferred to the fuel rail...

is it possible to take measurements at those critical points to see where the drop in pressure is actually happening? i am more of electricity guy and not much of hydraulics specialist, i just know that in some simplified schematics we use analogy with water transfers through the pipes to explain some electrical functions...

do we have any hydraulic specialists here that could chime in??

Here's a video on tests for fuel pressure at the fuel rail and problems.

https://www.youtube.com/watch?v=aITQclp7zIE

Since the pressure is going down when you rev the engine and you just changed the fuel pump it looks like you have a clogged fuel filter. Or the vacuum hose that is attached to fuel regulator is leaking. Did you remember to attach the vacuum hose to the regulator? You can connect a vacuum gauge to the hose (disconnect the hose from the regulator and install the gauge) to see if there is vacuum at idle and if the vacuum change when the engine is revved. The vacuum should drop when the engine is revved.

doesn't he have a new filter there? not to say that the new filter cannot be faulty...

He has a new filter in the truck, but it could be clogged with debris from the old used fuel pumps that he been installing in the truck He didn't wipe the sump where the fuel pump resides when he replaced those fuel pump so a bad fuel pump could have dropped debris in the sump. Or maybe someone dump something into his fuel tank.

Have you thought about throwing in the towel and taking it to a mechanic? I understand money is tight but you're nickel and diming your way to a solution. In the end it might be less costly and more expedient to take it to a qualified mechanic.

E4/B1 - Oxygen sensor controller, bank 2, deviation too great, deviation rich
E3/B1 - Oxygen sensor controller, bank 1, deviation too great, deviation rich
CB/B1 - Oxygen sensor control, bank 2, control limit, mixture limit rich
CA/B1 - Oxygen sensor control, bank 1, control limit, mixture limit rich

From your last scan of the truck it appears that the engine is running rich and not LEAN. So you shouldn't have the P0171 or P0174 code any more.

It could be that the vacuum hose that is connected to the fuel pressure regulator does not have any vacuum so the fuel pressure regulator is alway at WOT (wide open throttle).

I replaced both relays.

I had readings from the first time around at the pump, at the filter, and at the fuel rail. I'm posting a video in a few.

The vacuum is attached, I made sure of it before putting everything back together. Where does that vacuum lead to? Is it one of the lines that is connected to the rubber boot at the intake (1 of 2 hoses?)

All the F'n time. :(