Hi!

I have a H22A, (japanese specs) in my 92 prelude.

(92-96 Vtec H22 4G - BB 2157 10.6 : 1 200 @ 6800 rpm 161 lb/ft @ 5500 rpm Japan)

My idle acts kind of weird. When I am at a red light, it goes up and down (sometimes from 900 to 1 800 rpm). It's kind of annoying.

Some other times, my idle goes so low that if a don't push my AC button on and/or turn my lights on, my car will stall. And even then, sometimes my idle could be as low as 400 rpm when I am not hitting the gas...This is not right!?

What is the problem here, what should I do?

 

everything you need too know to fix a idle problem.
http://www.ef-honda.com/ben/Badidle.html