Rebuilt and cleaned my 85 nikki carb and put it on my 83. I have capped off/re-routed all the emissions equipment. Unfortunately...the idle is still pretty crummy and the idle oscillates. Anyway, I was wondering what effect the shutter valve has on the car when capped off completely. It would seem that it would just keep that valve open and just allow airflow to be controlled by the carburetor.

Plugs look ok...but a little bit brown(light). No other evidence of a vacuum leak...but I suppose its always possible. The items NOT capped off are the secondary ignition pots, the breather tube for the oil fill and I believe that is it. Thanks for your time guys. 83 12a w/72k, racing beat street header system, and the car also has a 3rd gen coil pack and msd ignition for the leading ignition. Contemplating replacing with stock. Thanks for any input!