04 Tahoe Smoke

[nicegy31]

Hi I am looking to see my options out there. I recently bought a how a few months ago and had the check engine light on. I knew it was the Cats.. I changed my cats out and the light went away. I also changed out the 02 sensor one of them not both because when I ordered them online one was right. The check engine light is the 02 sensor again. I noticed when I acccelerate I see a little smoke come out the exhaust through the side mirror. I have 120,000 miles do you think its time for a new engine? What are my options? Am I the only person having this problem? Thanks in advanced.