my 81 280zx starts good and reading is 1500 rpm but starts to lower to 600 rpm after 8 minutes of start and sign of dying .Please advice. Thanks

 

Welcome to ZDriver!!!

Have you checked all the basics?
-Timing
-AFM
-CHTS
-Air regulator
-Idle screw
-Vacuum lines (check for cracks)

 

I have replace air regulator.
waiting for the delivery of idle adjusting screw unit (cuz I could hear air coming from it).
Replace AFM with remanufactured one but the problem have worsen, so I put back the old one and its better.
I will check further for cracks on vacuum hoses.
What is CHTS?
Thank you for your advice.