I'm pretty sure it's normal if you have a bad o2 sensor but my car seems to smoke alot. The smoke is not white or blue so that rules out oil or coolant. Plus my engine was rebuilt about 6,000 miles ago so i'd sure hope it wasent one of those. But if i ever just give it a fair amount of gas alot of smoke will come out from the back. Not to mention the car runs rough. It's so bad that it'll turn my bumper black overtime. Plus i think maybe one of the valve covers is leaking which is in turn leaking onto my header and then burning causing smoke. I just wanna make sure this normal for having a bad o2 sensor and that i dont have bigger problems.

 

I didnt have any smoke when my O2 went bad, but maybe the way your tune is. Is making it run rich so that would create black smoke.

 

Replace the O2 sensor(s) and go from there.

 

Yea well it hasent been tuned since the cam so i knew it was running rich already. But im gonna get 2 new o2's