my toyota 4 runner is running bad with blue smoke the codes said oxygen sensor but i replaced it still the same help.

 

Blue smoke means its burning oil

 

Maybe the heater circuit?

 

hey, my cousin has a v8 4runner from 2003. it shoots out blue smoke just for a minute of 2 at startup. i read in a 2005 thread that it is mostlikely the valve seals. how hard is this to do, and is it really necessary to do other than for making the environment and other people happy?