take your throttle cable off and see if it idles down, i have found some celica that had throttle cables that needed adjustment , usually just loosening the nut on the valve cover that holds it will give enough slack.  if that doesnt work or doesnt do enough,   you may need to adjust the mixture(bottom of carb,ie the needle valve)
but it sounds like your linkage is binding so that it doesnt come to rest on the idle set screw properly

do you have a thermostat in your truck?? if not the coolant going thru your choke is not getting warm enough to open the choke

check these things,  if it doesnt work call LCengineering they have a deal on 32/36 weber kits for $309