I have been having this problem with my 88 it idles up and down quite a bit. It even does this with the iac unhooked. What could cause this? The car has no vaccum leaks and the timing is set at 8*

I can't figure out what could be causing this.

 

If it does it with the IAC disconnected there is a vacuum leak, you just need to track it down. It could be the IAC itself leaking.