I HOPE i GOT THIS CORRECT THIS TIME ..
I have 03 lb7 in a 3500 dually on the way home about mile from home fuel gauge went to 0 and fuel light came on and it lost all power it would rive at about 15 mls per hour I changed the fuel filter but it didn't help any . the filter was only half full of fuel so it it is not getting fuel I think someone told me it was a lift pump oriely's said it was inline sold me one but I have dropped the tank and followed the fuel lines all the way to the engine and not found a lift pump Help how do i pull codes with out taking it to dealership or plugging in anything ?? any ideas what this could be .. oh when moving some of the wires the fuel gauge came back up worked for few min.. it has 3/4 tank of fuel ...yes I know it was heavy to drop down but i put it back up now any ideas

 

Stock there is no lift pump, only the vans I believe had an inline lift pump. Your cp3 may be goin bad and not pulling the fuel up from the tank. Try priming it with the pump on the filter head?

 

I have it pumps up ok if you use the manuall pump it has no problem starting so it is not losing prime but if I pump it up then start it still has no power,
What am I looking for when I pump it up ??

 

Just filling the fuel filter and pump by pumping it . If it keeps sucking the filter down then I would say there is a blockage or something keeping fuel from flowing properly

 

I had been having much of the same problems in my 08 Kodiak. I installed an aftermarket lift pump, and that fixed most of my problems. the check engine light went out, no more loss of power after hard brakeing. however it still looses prime and lets air into the lines overnight, so it will start, then drain the filter then die. then will restart after the air is purged from the system.
The mechanic at the local dealership says they see this alot, and the problem is the fuel filter housing, and it needs to be replaced. so I have ordered one, once installed I will have replaced the entire fuel system from the intank module to the filter housing.
I have read however that the bleed screw on the filter housing will sometimes crack and allow air into the system, and is probably much less expensive than the entire filter housing. Ill let you know if it fixes the last of the problem. Note: the filter housing was probably the root of all my fuel problems, the istallation of the lift pump just overcame the wort of them but didnt fix it.