Nissan Repair: 280 zx turbo running too lean, vacuum hose, air meter

Question
The car is an all stock 5sp California car. It runs so lean that it won't
accelerate at anything above 1/8th throttle. The AFM is new
remanufactured unit and injectors checked out OK. Feul pressure is 38 psi
with vacuum hose off and holds steady under acceleration. After several
tanks of gas car continues to run poorly.  Any suggestions how to correct?

Answer
Rick,

Recheck the air meter.

Check for unmetered air.  That is, if there are any places where air can get in behind the air meter.  If there is unmetered air the car will fall on its face as you indicate.  A cracked hose or a misaligned hose where the clamp is not holding tightly.  A PCV fitting and even a stuck waste gate.

Check throttle position switch.

Check for a melted converter and any other restriction in the exhaust.

Check the oxygen sensor.