Fuel Pressure Dissapearing!!!!

Here is my problem. After I added a fuel pressure guage and regulator I noticed I had over 9lbs when I the engine is first started so I adjusted to 5lbs. After driving awhile I noticed I the car was fuel starved and would not go over 30 MPH. I checked fuel pressure and noticed I had about 0. So I readjusted the regulator but can only get to about 3 or 4 lbs.(The regulator has a range of 4 to 9.) Sometimes the pressure still disappears.
I have changed the mechanical pump, checked the fuel filter. I have new lines from the pump to the carb.
What's going on?? Why is there 9lbs when engine is cold then drops to 0,1,2,3 max of 4 when warmed up?
Anyone had this problem??
Engine is a 351C 4V. Carb. is an Edel. 750VS.

Do you run a liquid filled gauge? There has been a run of bad ones, especially XRP, when they heat up, the liquid expands and it measure the pressure difference inside and out. WHich is zero when hot. I chased the same thing on two until we figured it out, it was the gauge all along

might have some trash in the tank,might take a little while for the screen to plug while running,but if you let it sit a while the trash would kinda fall off of it.just a thought

I am wondering why your using a fuel pressure regulator when you have a mech. pump that will normally put out 9psi?Is it a stock fuel pump?Or aftermarket high pressure/high flow?

I installed a pressure guage because I was starving for fuel and couldn't get over 40MPH. .Once I intalled the guage, I noticed I had 9 lbs when I started the the engine. So I adjusted pressure to 5lbs. After driving I noticed the pressure dropped to 0, so I readjusted but the best I can get is 2 or 3 at idle. This is the problem I am trying to solve.
I am going to use a plastic gas can to suck up fuel right at the pump. If the pressure comes back, then evidently there is something wrong with the fuel line. I visually inspected the rubber hoses. They looked good, but I have been told that they can colape on the inside.
Any other suggestions?

pickup in the tank could be clogged, very common in older cars. Especially those that sat for any extended period of time.
[addsig]

I replaced all the rubber hoses and blew out all the hard lines. It did not make a difference. I know I need to check the pick up and strainer, but can I remove this unit from the front of the tank if the fuel level is 1/4 or lower, without droping the tank?

Still have the problem!!!
Today I pulled the pickup out of the tank. There is no screen. I had removed it when I first cleaned the tank about a year ago.
I looked inside tank and could find no foreign material.
The pickup tube is clear..
To date I have check everything from tank to fuel pump to carb. The only thing left is the Fuel Pump itself. It is stock one from Auto Zone.
Is there anything that I have missed???
Is it possible the I have installed the fuel pump incorrectly?

boy, heres a thought. Could the vent on your tank be plugged? maybe your drawing the tank to such a vacuum the fuel pump cant pull it anymore. See if your problem is still there with the fuel cap off.
[addsig]