Actually I've replaced (3) different O2 sensors in the past year, code #0144, #0136 and #0156. If you have a great flowing exhaust I can't see gutting the pre-cats making that much of a gain to justify it. I mean REALLY, how much are you going to gain in hp compared to the gain in CEL's your going to get? One thing you'll need and it may save you money in the long run, is some type of scan tool that not only tells you what code your getting but one that tells the millivolts your O2 is putting out. I say this because that CEL could be your MILS (homemade or store bought) going bad and yes I have experience here too
In closing think about this, is the extra 3-5hp worth the headaches of CELs, CELs because of defective "homemade" MILS, defective store bought MILS which cost about $70.00 by the way (that could be money spent towards another mod i.e. bigger used TB), see what I mean
