Check your vac lines, I have had those little bastards pop off and it drives you nuts trying to figure it out. Hopefully you can see most of the lines, just go over everything really well its probably just something stupid thats easy to fix, those are the worst kind of problems. Could be leaky injector o-rings, or an intake manifold leak, I am in the process of hunting down a crappy idle at the moment also. Please update if you figure it out so we can all know what to do:)