2000 7.3's have a lift pump in the tank but i have heard of some of them having a pump on the frame rail but I have never seen one. Pressure readings are taken at the fuel rail plugs at the front of the RH head, the rear of the LH head, and at the fuel pump outlet. The fuel pressure should be over 30 PSI, but anything below 50 PSI will cause an injector knock. If the pressure is low at either head, replace the check valve at that head's fuel rail inlet. If it is low at both heads and the pump outlet, check the pressure regulator at the fuel filter return line for debris or a split o-ring.

 

The fuel pump is on the frame rail, they do not have one in the tank

 

There are two fuel filters on the truck 2 little fingerstyle filters in the tank one on top of the engine. I have seen this on my friends truck no power would barely idle. We check fuel pressure at the pump and hardly any dropped the tank the lamination inside the tank was coming off in pieces plugging the 2 fingerstyle filters. Can't hurt to look. Have you owned this truck a long time?

 

Here's another thought you might be getting air in the fuel. That would make her stumble and lose power. Do you have access to a scanner like auto engenuity like Big horn said that way you can check sensors and maybe even fuel. Air and a clogged filter will not set codes

 

I have scan tools but no check engine light to read, tryed anyways and nothing. Just dropped the tank very dirty cleaned it and put it all back together. The fuel pump is on the frame rail not in tank and at idle I do about 58psi in the faster I drive the lower psi get I hit 30psi by 25mph. So I going to replace pump now

 

Replaced pump, cleaned tank and pick up screen in sending unit and am still losing fuel pressure. Is their a check valve anywere that can but stuck open or something dumping all my fuel back to the tank?

 

There's a regulator in the return line on your return line at the filter on your engine. Take it apart and clean it and check the o ring real good. Probably good practice to just replace it imo

 

I just bought a whole new one and have it coming. Hope its it.

 

There is no return line on a SD 7.3

 

Their is a fuel pressure regulated on top side of fuel filter housing that controls when fuel is returned to the tank... according to the Ford 7.3l book.