Javspo0lin

Hey guys i started experiencing a rough idle on my sc300 and shaking also. After experiencing this issue i went ahead and did a spark plug change and TB cleaning. I gapped the plugs to .40 which was the recommended spec, and i cleaned the TB according to a thread on here and made sure that i installed all the vaccum hoses also. While doing that I also cleaned up the Idle Speed Control valve (outside only( When the car is warm it drives and idles fine the problem only comes when the car is cold. I checked the CEL light and it was code 27 which is oxygen sensor. Can anyone please guide me to what i should check next.
Thanks in advance for anyone that wants to give me some input

Javspo0lin

i will also add that the car has 109,000 miles ans 5speed in case it helps determining the problem