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So apparently, I have bad cats. My truck keeps throwing P0420. I'm not getting any issues with it running bad, lack of power or whatever. I'm thinking about cutting the cats out entirely (no inspections here), straight piping thru them, and replacing the muffler with a flowmaster to prevent the rumored muffler blowout from increased pressure getting to the muffler. Also installing/making mil eliminators.
What are your thoughts about this? Any foreseeable problems with this band-aid route?
Yes. You'll still continue to throw that code. If for whatever unforseen reason, you are forced to move into an emissions area, you'll be unable to register the truck, due to the removal of the eqipment - which is illegal by the way. I'd just pony up the bucks, and get it fixed right. You'll at least be comfortable that the job was done that way it should have been.
I would definitely replace them. Don't wait till they come apart and clog the muffler and spray sparks all over the road. I just replaced both cats on my 99' f150/5.4 and a flowmaster muffler for around $500. They weren't ford cats, but they work great. The truck runs better and sounds great. Getting rid of the cats is definitely not the answer, I've seen too many problems arise from that.
If you install the MIL eliminators it will not still throw the code. I have had them on my Crown Vic for several years. Oh, no code and the converters haven't come apart either.