I'm looking to delete my cats here soon for some high flow cats. What all should I expect as far as check engine codes etc

 

If you install good high-flow cats, you shouldn't get any codes. If you install cheap ones that don't work well, you will likely get a P0420 and P0430 codes. If you do get those codes, or if you run without cats at all, there are 3 ways to get rid of them. The first, and most expensive, is a computer tune to turn off the cat monitors. The second, less expensive way, is to buy or make some MIL eliminators. These plug into the rear O2 sensor plug and simulate the signal the computer is looking for from the rear O2s so it tricks the computer into thinking the cats are still present. The 3rd and cheapest way is to go to your local auto parts store in the help section and look for spark plug non-foulers. Here is a link
http://shop.advanceautoparts.com/p/d...2008/5017718-P


You will need 4 of these total. 2 of them get a 1/2" hole drilled completely through them, and the ones with the hole get threaded into the ones without the hole, then the whole thing gets put on the rear O2 sensors and then the O2 sensors with these extensions on them get threaded into the exhaust. What this does is move the rear O2 sensors out of the exhaust stream, so they respond more slowly to any changes in the air/fuel ratio, which exactly what would happen with functioning cats, and exactly what the computer is looking for to know the cats are working, so you won't get any check engine light.

 

Great news! Thanks! I knew about the gotts o2 mod and I didn't know if I would still have to do it with high flows or not.

 

I am thinking of trying this on my 2008 F-150. Hopefully it works. Good information on here!!