[81-280zx]

the first time i start my car for the day i cant get it to stay running .
when i start it, it will idle low then die. i have to keep my foot on the gas
when i crank it over to keep it running, after that its fine. i think its my cold start
valve. if anyone knows the problem please tell me

 

[z_man300]

If it starts, I wouldn't suspect your cold start valve; it's only on for a few seconds to help start your car, not keep it running when it's cold. Maybe the auxiliary air regulator's failed shut? That would prevent enough air from reaching your engine when it's cold and has a lot of friction (cold oil, etc.), subsequently causing too little gas to be injected to overcome the friction, and your car dies.

By stepping on the throttle, you're essentially giving the car the air (and corresponding gas) it needs to run when it's cold. It could also be a bad temperature sensor not giving you enough enrichment at cold temps.