could be a million reasons. ranging from bad fuel, vacuum lines not connected, plugged up fuel filter, bad/dirty carb.
If your 1983 Datsun 280ZX won't idle, it could be due to several reasons, such as a vacuum leak, which disrupts the air-fuel mixture, or issues with the idle air control valve. Additionally, a dirty or failing fuel injector, a clogged fuel filter, or problems with the ignition system could also prevent proper idling. Checking the fuel delivery system and ensuring all connections are secure may help diagnose the issue. Lastly, a malfunctioning throttle position sensor can also affect the idle speed.
vacuum hose leaks off the carburetor.
1990 gmc p/u 5.7 wont idle showing code 12
your truck wont idle correctly when its cold, because its cold...and nothing runs correctly when it's cold. your truck wont idle correctly when its cold, because its cold...and nothing runs correctly when it's cold.
Usually the spark plugs or the timing.
Try the idle air control motor
the idle solinoid may need changing, or its power source is not plugged in or working. If the solinoid is not powered the carby wont know where to idle, it will drive fine but wont idle when you pull up at lights ect.
u dont set the idle the ecm does the setting througt the air idle conrtol. If it wont idle u need to replace the aic motor on the th0rottle body!
The A/C idle compensator solenoid is not functioning. This should be located next to the carb.
possibly a vacuum leak, low fuel pressure, or the idle air control has failed,
Idle Air Control Valve....if this breaks you car wont idle properly....the rpm will go up then down all the time when idling
try cleaning your carburetor thoroughly