I have a 2006 galant 4g69 2.4L and is it the 02sensor or cat in bank 2 ? I cleaned the EGR and still have a low idle.... of and on sometimes when the trans is in drive it idles low or reverse but when its in neutral it at 600 rpm

 

Could be either and I've seen it end up being one, the other, or both in the past. And changes in how the engine is running doesn't seem to consistently help pinpoint which.

Here's some info on sensors and how to test them if you're inclined.
http://www.mr2.com/TEXT/O2_Sensor.html

Check your warranty. Emissions components should carry 8yr/80k miles warranty in the US.

 

I am not getting an o2 code just that one there. I do have and OBD2 scanner to check the voltages. Would it be worth it to take off the cat to see if there is any blockage that i can look for? I did take off the secondary cat because there is no o2 sensor on it but, I had that off for like 3 months and no problems until now.

 

That code is an O2 sensor related code. It's sensing that either the cat isn't working as it should OR the sensor is faulty. Hard to nail down which until you do the sensor testing. I wouldn't pay to have that done because it's cheaper to replace it than pay someone to test an old sensor. Rockauto.com carries the sensors for much cheaper than parts shops.
I don't think you will be able to visually see anything to help diagnose the cat condition.

 

Ok thanks. Well, I did take off the secondary cat and silencer because there was no O2 on the cat I have a custom exhaust i did that to allow more flow. The mechanic at my work said it was not an o2 code just a cat code and said that if it was it was an o2 isshue it would be an o2 code.