Not sure if this is the same setup as my Pacer carb, but there's TWO idle screw settings on the linkage on mine...one is the fast-idle ( choke ), the other is the off-choke idle. You can adjust them independently, so the off-choke setting could be too low, and needs to be brought up a half-turn ( the screws and step-cams do wear over time, changing the settings some ), if there's no other problem with the car. Obviously check for bad vac hoses, partially disconnected, etc. KISS principle applies ( Keep It Simple, Stupid! ), so look for obvious problems first before tinkering with the carb settings! Good luck! Jerry