I just .. I mean Just had this same exact problem in my 77 with a 82 turbo motor. I went through and replaced dizzy cap, spark plugs, rotor, checked output of spark.. It was just getting way too much fuel. So I went to a buddies place and grabbed some stuff from his 280zxT parts car.. Igniter, AFM, and ECU.. I switched the igniter out.. still the same problem. I switched the ECU.. BAM fired right up.. So I am thinking something in the ECU either went bad or worked its way loose. I also cleaned all of the contacts to the ECU , TPS , AFM before replacing anything.. So. Might want to try a used Turbo ECU from somewhere.. I sure hope this helps..Good luck.