rough idle, possible vacuum leak?
 

So my idle bounces around a little bit. A mechanic at my work told me it could possibly be a vacuum leak. If it is this, does anybody know where to look? If not what do you think it is. I have been doing some searching but can't quite find what i am looking for.
Thanks

What year car do you have and what mods do you have if any? Turbo or non turbo

all stock, non turbo, 86 base model

mine does the same thing. Was a LOT worse a few weeks ago but then I got my DMM out and reset the TPS and then reset the idle mixture. Now MUCH better and smoother. I also hooked up a plug that I never noticed was unhooked over the past few years and BOOM, 3k rpm warmup :p:

If you've set your TPS after warmup and reset the idle mixture then ... I can't remember the third thing, but that should help a lot. You got a FSM?

EDIT: is it just your idle or does it do it when you hold the throttle at different points on the rpm range?

Ok... First what is the DMM? How do I reset that and the TPS? Second, I have the 3k rpm warmup. Third, I have a Haynes manual. Fourth, yes it is just my idle.