co mix screw

[Delorean17@xxxx]

Hello,
I have been working on my project car for some time now and havent been 
able to figure out its odd idle and poor acceleration problems. The frequency 
valve is working properly so I thought the problem may be related to the 
intake system.
I thought it might be a good idea to check the co levels and adjust the 
screw as necessary. I removed the intake(both halves) and found that the 
metal ball(plug) that covers the hole was missing(nice sized vacuum leak I 
guess). It also looks like the screw is in as far as it can go. I am 
guessing this could be my problem although I dont know for sure. Where can I 
buy one of these plugs at? also, what type of head is on the co mix screw? 
you cant really see it through that little hole.

Thanks
David