My car idles at 1600-1800 for some reason and blows black smoke with little particles in it. blows smoke when it idles and when i drive. runs really rich. driving from school and home burns 5 bucks of gas and school is less than 1 mile. plugs are black and when i pull the iacv plugs it idles normal. using a p06 chipped. did this after i swapped a z6 head onto a y7. when i pull the chip out it blows even more black smoke. any help would be appreciated.