When fuel delivery goes bad, it could be:
Some trash in the system that's migrating through it.
Rubber inside a braided or rubber-ish hose has become a "flap" that cuts fuel supply.
Sticking float or bent/binding hinge tab.
Dirt in an air bleed, needle/seat, or jet.
Something closing off the pickup like a rag in the tank (DAMHIK).
With 1/2 fuel line, I've noticed that a stock mech pump alone won't keep it pressurized adequately.
Tank not venting.

I know some of these won't be creating your problem, just listing them from experience.