I hate to be the guy that only join a forum to ask questions but it is what it is.

I recently bought (my first car) a 94 civic ex with an h22a swap and LSD trans.
The car runs great, well taken care of and performance is great too. The only problem to speak of is the idle. I know its common, idle goes from 1000 rpm to 1500 rpm up and down while not applying throttle.

I haven't tried much of anything yet to fix the problem but the guy I bought it from said that he cleaned the iacv and it stopped doing that for a while. It also has a coolant to TB bypass.

Where should I start to fix this very annoying problem?

 

Start with cleaning the IACV. Use brake parts cleaner and a q-tips to get in and clean around the plunger. Try searching next time or looking in the stickies please. There are plenty of resources on remedying this problem.