[4Door]

usally its from unbuned fuel in the exhaust, shouldnt worry to much, all though ive heard of peoples mufflers blowing up from it...haa

 

[4Door]

does it blow black smoke when under acceleration

 

[4Door]

yep. its runnin rich allright, wach out tho, it could foul out your plugs and gas milage will go away also...