dirty fuel lines, filters, and tank pickup screens are my first guess, closely followed by fuel pump problems. You have two fuel pumps...an electric by the tank and a mechanical one on the engine. The electric pump runs only during the starting of the car; it's to prevent vapor lock. If it gets clogged up and fuel can't flow through it easily, you get the results you describe. Also...you can try installing a cheap fuel pressure regulator on the return line going from the fuel line back to the tank. Spectre is the brand I used.
73 240Z very orange
Dual Weber DGV's, header and 2.5 exhaust
Electronic dizzy with G.M. HEI module
Tokico Struts/Springs, Full Poly U bushings
Daily driver, all work done by me