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.
Drive it. It will relearn itself. It may take a few drive cycles.
If i were you i would start with the catyletic converter ,it'll start cold,start for a minute then stall, start back up but wont drive ,idle, but not drive ,check it out.
Loud idle? no, not turn over ,yes
Carb needs curb idle adjusted or rebuild.
my avenger does this when its cold out and it is becasue of the spark plugs need to be changed
inproper choke setting
1990 gmc p/u 5.7 wont idle showing code 12
chk. compression,150 is normal,about 120 or less in no. 6 and it will miss at idle,but you wont feel it under a load.
safety reasons
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.