My 2004 accord 2.4 has hole in flex pipe and is getting louder . And check engine light came on . So I tried muffler cement and lots of muffle bandage . Car got a little quieter . So when I start engine it start right up and idles good . But after few minutes it starts to surge . First time it did it engine was smoking bad . So took of muffler patch and tried again. Same thing engine surging . Po137 code says something about 02 sensor going below 400 milivoil. Any ideas ? Is it bad o2 sensor or bad computer monitor ? Any help appreciated