I have a 86 chevette 1.6 rough idle when put into gear.

I have a 86 chevette 1.6 with electric choke. It is idling very high in park and neutral. But when you put the car in gear. The idle comes down way low and the motor almosat stalls. Once you get it on the road and accelrate it runs good. The SSC actuator vaccum is not on and I can not find where to plug the vaccum line into comming off the actuator. Could this be the problem with idling when putting the car in gear? Does anyone know where the vaccum line should plug into comming from the ssc actuator? thanks