Low Idle Problem On 2000 Civic Ex

[illicon2003]

I've noticed an extremely low idle recently.. especially after letting the off the acceleator. I'm pretty sure I noticed the problem after replacing the 02 Sensor with an older one I had laying around (The CEL is off), a few weeks ago. The car is tuned up, everythings fine ignition wise(I think) I did a search and I read that it could be a problem with the brake booster and air bubbles. I was told by the honda dealership that when working with power steering(Dumbass friend cut the hose), I'd need to bleed the brakes so as to eliminate air bubbles. I haven't done that, so could an air bubble in the brake booster cause the vaccum leak? Some other stuff I read about was adjusting idle and cleaning IACV, but I'm a little reluctant to do those since I've never done either before. Also, I just wired up an AFC last night. I'd like to iron out all these little problems before the turbo goes on, so it will be easier to fix problems associated with that. Please help me. thank you