Idle drop?

Ok, well I got everything back together and running on the '91 accord. It runs and drives great, but when you rev it up, it drops back down really low to like 300 rpms, then comes back up to like 700. It sounds like it wants to quit sometimes.

What would do this? Also where is the idle adjustment on that intake manifold? Thanks again!

Um, could be your plugs, or a vacuum leak.