When I failed my emissions I was told it was because it was running rich. I put some fuel system cleaner in the tank and I'm halfway way through the tank now. It still runs rough, at times, at idle. When it's running rough it has bluish smoke and black flakes on the ground under the tailpipe. I figure the black stuff is from the cleaner in the fuel but I'm not sure. I disconnected the AAP and it didn't make a difference.

Thoughts?