Leaning it out?
 

If I use my tuner to lean out my car just a little tad wouldn't the o2 sensors on the car throw a CEL to let me know if the car is running too lean or not? I have heard the tune that come preset into the tuners are a bit rich just to be on the safe side so I figure if I lean it out just a little little bit wouldn't I be right on the spot and if i go 2much wouldnt the o2 throw a CEL.

Not neccissarily. I wouldn't lean it out unless you have a way of reading the a/f ratio.

It wont tell you till the car is very lean.

But wouldn't that mean that the car is at an "acceptable lean" to the computer? bcuz I read that the o2 only throw codes when it goes from acceptable rich to unacceptable rich and same for the lean .

No man it does not really work like that for tuning a car. Without a wideband you will never know wtf the a/f ratio is.

.... unless of course you have a psychic giving you a hand. :D

Lol I don't think even a physic would know only advice from them would be I see a blown motor in the future. Well I think I understand now that there no is no way around either a dyno pull or a wideband both very pricy lol.