Code P0420, use rear o2 anti foulers?
08-08-2011, 05:49 PM
#1
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Code P0420, use rear o2 anti foulers? So, I have been battling this code for some time...but now, it is war! I have a 98 SS, with Flowtech LT's, custom Y with high flow cats, and this week installing a SLP LM1 cat back. I am so sick of dealing with this code(P0420). I have resealed my headers 3 times, with Felpro gaskets, with little luck. So, like I said, it's war now!! I am going to get Percy's seal for good header gaskets, from Speed Inc., and Percy's collector gaskets. I have done some research, and found that most likely, this code is do to the high flow cats. Keep in mind, that I do not have the rear o2's tuned out. I am kind of on a tight budget, and I was wondering if people have had any sucess with the anti-foulers, that the rear 02's fit into? If so, how much, what size, and where can I get them? Any info would be greatly appriciated!!!! 
08-10-2011, 10:07 PM
#4
You can get spark plug anti foulers, and drill them out with a 5/8 drill bit. you will need two a side of the small ones. They sell them at autozone in packs of two for 5 or 6 dollars. It will trick the computer into seeing less emissions and getting rid of your p0420 code.
08-12-2011, 09:51 PM
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i've been having that same issue with my rear o2 sensors and would like to keep them please someone explain anti foulers, how to apply? where to get them and how to make them.thanks in advance... the oldman
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08-12-2011, 10:59 PM
#8
If i were you, id just get the code tuned out. Im not sure how anti foulers work, but the code is due to your rear 02 sensor. Not the front one. The front 02 sensor reading is supposed to fluctuate. The rear one is supposed to be more stable since its after the cat. When the cat is removed or not working properly, the rear sensors wont be stabilized and theyll read close to the front ones. When this happens, the p0420 code is thrown out there cus the front and rear sensors shouldnt be alike.
