86 zxturbo starts but boggs down not getting enough fuel

[BigFig]

I have a 1986 300zx turbo manual. The car starts and runs but boggs down and seems to not be getting enough fuel. It has gotten progressively worse. I have replaced multiple fuel filters. Dropped the fuel take. It is clean, no dirt or rust. I replaced the fuel pump. I replaced the fuel pressure regulator, the mass airflow sensor, main computer and throttle control sensor.
Any ideas?

[Rubyz32]

Have you tested your injectors? Have you run codes? Vacuum leak? If you have an fsm, try the diagnostic procedures for your symptoms. If not, definitely get one. If you need parts, PM me, I have all kinds of stuff since my last 7 z's were Z31's.

[BigFig]

Have not tested injectors. The car will sometimes run perfect for 1 hr or more. Other times it runs for a few minutes. It is definitely starving for gas when the problem occurs. Fsm? Do you mean service manual? Yes I have one. I have run the computer codes from the service manual and everything says ok. My guess is ethanol gas has damaged something. I have replaced all fuel lines under the hood.