Does it happen when the engine is cold or when the engine is warm and ambient air temp is cold? I dont think there is a means for the car to warm intake air in cases of cold weather, so im wondering if the throttle plate is sticking. Actually i think that should be the only thing it could be. Disconnect your throttle cable and work both the cable and the linkage to the throttle plate. cleaning and inspecting the throttle plate isnt easy on this engine because it faces the firewall. You might have to remove the throttle body and clean it, clean and lube the linkage and cable and inspect the return spring. Also clean the egr passages ( 1/4" hole at the bottom of the intake around the throttle plate )
If not maybe an injector is staying open.