help, she died

[imfixinmopars]

thanks for all the input on trying to get this ol truck going,but it finally gave up on me,1984 6.9,ip stamped rebuilt,unknown miles.new lift pump,starts cold and hot like new!i believe good power,...but as i asked before,the engine will suddenly loose power and act like shes running out of fuel. i will shut off the truck and right away start it and drive off running strong.happens once in a while,1/2 tank of fuel.no leaks,bypass water sep.,well today it lost power on the way home and never regained it.limped it home25 mph.removed the ip pump cover and seen it was full of fuel and fairly clean.pulled ip and didnt see anything funny,but i dont know what to look for.when it was running,poorly, at idle i cked the fuel psi at the shrader valve and got 4 psi max.is too low?is the ip plugged w/ something? i though it was the fuel shut off solioid,because of the shut off and start and go situation.it clicks good,help me see something i missing.