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

 

It sounds like you may have a bad sending unit in your fuel tank, that may be sending a false signal to your ecm telling it to put the motor into a limp mode.But also you said when you moved some wires the fuel gauge started working, that sounds like a connection problem. And does your dash have a digital read out?

 

I'm with you 97...... sending unit.