In the tank of your 6.0 you have a pickup tube- on the end of it is a plastic piece that commonly breaks. This causes 1/4 tank issues (truck will act like it is out of fuel). The HFCM (fuel pump) is on the drivers side frame rail just underneath the drivers door. Are you using anything to monitor fuel pressure? Minimum of 45 psi is required, recommended to have at least 50 psi in order to keep the injectors happy.

 

Yes I have an Edge CTS 3 to read all of that stuff. Need to check fuel pressure though. The fuel bowl where the upper fuel filter is located does not fill up at all when the key is turned to on position like it should if the fuel pump is working. And after getting down close to it the pump(HFCM) it makes noise like it is running and pumping but obviously not if the fuel bowl is not filling up? Next down the list would be pickup tube in the fuel tank or if the 2006's have the in-tank fuel pump as well? Any ideas? Could the HFCM be plugged?

 

None of them have a pump in the tank -- that information is false

How much fuel is in the tank?
Have you changed the filters lately?
Have you checked the fuel lines for rodent damage?

 

I would pull that fuel filter to make sure there are no clogs in there, go ahead and change them both if you haven’t. Drain that water separator while you’re down there.

You can also pull the whole HFCM off the truck and remove the pump from the module. When I took mine off a bunch of sludge came out and that’s what was giving me low fuel pressure- I replaced that pump with a unit from Rockauto for around 100$ and my fuel pressure has been 55+ ever since.

Your CTS has the ability to show fuel pressure but only if you have added a fuel pressure sensor to the truck yourself. Once you figure out your issue you can add a sensor to the test port on the upper fuel bowl and read your pressure from there.

 

1) The pump can make noise but not pump.
2) The whole hfcm can fail leaving the pump sucking air. It's actually the irreparable check valve in the hfcm that causes this.
3) The pickup foot inside the tank can deteriorate, this causes an "out of fuel at 1/4 tank" situation.

I've had the first 2 of the 3 happen. I pulled the return hose of the tank side of the hfcm & pushed air through it. This test put fuel in the hfcm, showing the pickup foot to be good and not clogged. So I moved on to the pump.
I do not remember exactly how I determined the pump was bad, but I figured it out pretty quick (I think I ran a hose to a bucket of fuel).
When my hfcm went bad, I did the air test, then swapped pumps. The hfcm was dry on the pump side both times, replaced the whole hfcm.
The pump can be replaced w/o removing the hfcm from the frame.... It's 3 hex head screws and the electrical connector.
Looking back, on a truck with 200k on it, I should have replaced the hfcm for $400, vs buying a fuel pump for $150 and eventually doing it all over again. I would have, in the long run saved the ini $150 for the pump. The hfcm comes complete with fuel pump and filter (but no upper filter, so that's part is pointless IMO).

Anyway, verify that you are getting fuel from the tank, then replace the pump or hfcm.