I'm not lucky enough to get MILS. There is no soot on my bumper. I have never changed to o2 sensor. It runs much better before the engine is warmed up, or if the weather is cold. There used to be sporadic moments where it would run strong, they were far and few between, and no longer occur. I believe its fuel related. I Ordered 4 new injectors, broke one of them, been waiting 3 weeks for the replacement (it was back ordered) I plan to replace the fpr and fuel pump as well. If that doesn't fix my problem, its bye bye prelude.