Hello there my fellow family members! My name is Shane, and I'm 19 years old and a Paramedical student.

I own a 1977 Datsun 280z, and I need some advice/help! I've recently had some issues with my Z. My Z starts up beautifully every time, but idles around 1,100-1,000 for a good minute or so, then dies down to 900-700 for five to six minutes, then slowly just dies out. It will start up every time even after it dies out. The idle times are different after every consecutive start up. I personally reconstructed the fuel injection system and all the fuel lines. I might just need to adjust the idle speed? or maybe the vacuum valve is leaking? But for some weird reason as soon as I try to drive the car it dies out.

Any Ideas? Thanks friends!

Welcome to NICOclub!

I've revised your title to reflect the nature of your problem (also removed personal info).

Here at NICO, we have Factory Service Manuals available free to members. Take a look at the link in my signature and find the FSM for your car and you'll have all the info you'll ever need to make the repair and try to diagnose it for yourself while help is on the way.

Sounds like your idle just needs adjusted. There is a worm screw and stop nut on the TB that limits how far the tb will close. IIRC 850 is the idle rpm, most likely someone set the high idle too low so when the iacv closes it can't sustain the 850 rpm idle.