I have a 96 gsr with the original skunk 2 manifold and on the back of the manifold there is an extra vaccum nipple. Should this be connected to somthing or just capped off. When there is nothing there it idles high then throws a cel. But when its capped off it runs normal but seems to idle a little low.

 

Yes you are supposed to plug it and if your idle drops then adjust it back to normal