do you have cruise control on the truck if so try to disconect the vac from that. my old d-50 had that problem when i started it it idled realy high and i disconected the cruise control under the dash and it ran like normal.
no cruise control but i got it running really good now and i can really feel a performance difference...in loving the weber...how high are you guys running your choke...mine is running about 2500 when the choke is on and normal idle when it turns off.