if you don't mind a quick add to the chat, IIRC, those carbs also had some high idle solenoids (and something else I think ) that interacted with the little "puter" on the passenger fender well. It could be that it's trying to compensate for something else that is disconnected? or? My only experience was to remove it entirley.(the carb) and the "puter".unless you could troubleshoot the problem. I know that carb kit is expensive, and a rebuilt one is very expensive...
That's correct John...they have a feedback system from the Idle Control Module and a plunger type of control on the carb...if it's working and connected and the choke is open...hmmmm...
i don't have the manual, but i have timed the truck before... when you disconnect the vac advance from the distributor, it idles about 800 RPM, which is what the factory calls for, so i would guess the timing is within a degree at worst...it was set at 8 deg BTDC, IIRC, that's what is listed on the core support sticker... do you think it would be leaking between the carb and intake or between intake and head? reason i asked is that i am getting a phenolic intake spacer (custom made) anyway, so that would be fixed before too long, and a carb gasket shouldn't be too much, right?
Could be the spacer on the carb or gasket needs to be replaced...
After reading what John posted I remembered there are two wires going to the carb...one for the choke and one for the idle control...
Take the breather lid off the truck and run it till it warms up...the top of the carb should have a butterfly valve that is your choke...this should be WIDE OPEN when the truck is warmed up...if it isn't then the choke is not working properly...it is an electronic choke and if the wire is not connected or is otherwise not working your engine will run very high idle...it will also backfire and be sluggish because you are not getting enough air (rich fuel),...
If that is not the case...find the other wire and see where it connects...if at all...that is the high idle kick down where it should run...make sure that is connected and if not that could be what is wrong...
Anyway...another question...
Are all the vacuum lines and the air pump still on and connected? Some people take them off to try to correct a problem but this can actually create more issues...
The timing sounds about right at 8*...with vac line disconnected...but you can still try rolling the dizzy if all else fails...
Pics or videos might help also...closeups of the carb and configuration might trigger someone's mind...