P0420 code what option should I do???
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Teching In
Joined: Jan 2018
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P0420 code what option should I do??? I have an 02 Trans Am Firehawk SLP with 54k miles that I purchased about three months ago. about a week ago with a full fill-up i added a can of Techron complete fuel system cleaner as maintenance and yesterday the "service engine soon" light came on. I have a code reader and cleared code P0420 which appearently is a bad cat converter or 02 sensor. My question is should I replace both the cats and could the fuel injection cleaner have caused this issue? I'm about to have some modes done in a few weeks, a compition cam and headers. If I do replace the cats should I go with high flow cats like Magnaflow, replace them with oem or just omit them when I have the mods done?
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
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From: Virginia
This depends on whether you have to pass emissions or not. My car is registered in an area where no emissions are required. It's been probably 10 years since I've had cats, unless you count the type that hiss and scratch.
I would start by swapping the O2s, if you are trying to keep the cats. Additives can affect sensor life. Did you get the code for both banks? O2s are a lot cheaper than new cats.
I would start by swapping the O2s, if you are trying to keep the cats. Additives can affect sensor life. Did you get the code for both banks? O2s are a lot cheaper than new cats.
