Just bought 2000 I30T 136k...white smoke at startup?

[Brandon85]

Hey all...I just purchased a 2000 I30T with 136k for $5000...its in cherry shape except for the driver side power seat wont go forward or back, and the compartment above the clock is broken. However after I got it home, I started it again about 2 hours later and a cloud of white smoke puffed out for like 5 seconds, then was gone. It didn't smell like coolant or oil either. The car runs perfect, and I started it like 3 times and drove it at the dealer twice, 2 seperate times before buying, no smoke. The car drives great. When I got up for work today, no smoke. No engine light on either. Anyone?

 

[Brandon85]

UPDATE: On my way home from work the check engine light came on...heated o2 sensor..could that be causing the smoke? Or is the O2 sensor malfunctioning because of the smoke...