Anyone ever have this one? My check engine light popped on the other day right as I hit 99K. AutoZone read the code for me, P0420, catalyst reporting under threshold Bank 1. Dude sold me a bottle of CataClean, I ran it on a 1/4 tank like it said. Light went out for a few days, now back on. May try another bottle or something similar one more time, then I fear I may have to take it to the dealer.

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Posted by jpainter6174

Boss city

Member since Feb 2014

5933 posts

Posted on 2/13/23 at 11:03 am to tigerbait1970

Google Down stream 02 sensor spark plug defouler, there's step by step videos to get this problem solved.

It works, however its not the right way to fix the problem.

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Posted by Cracker

in a box

Member since Nov 2009

18912 posts

Posted on 2/13/23 at 11:04 am to tigerbait1970

Pull the o2 sensor and clean it see if that helps

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Posted by holmesbr

Baton Rouge, La.

Member since Feb 2012

3565 posts

Posted on 2/13/23 at 1:23 pm to tigerbait1970

My project car throws this code. On the highway it gets hot enough to work normal. Around town it doesn't reach the temp threshold. I will probably order a new cat at some point. New O2 senors didn't fix it. Or a gallon of toluene in the gas tank.

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Posted by Pirate0714

Baton Rouge

Member since May 2016

480 posts

Posted on 2/13/23 at 2:15 pm to tigerbait1970

Exhaust shop and prolly change your converter. You can try to run a can of seafoam with a full tank of premium gas. Might help, but if you already tried the cataclean, may as well go ahead and get a quote ready.

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Posted by Jeebus

Member since Dec 2015

169 posts

Posted on 2/14/23 at 5:54 am to tigerbait1970

I had the exact truck 2018 f150 2.7 and had to get my cat converter replaced at 73K miles. Threw the same code and would go on and off at 100K.

I was losing coolant too and couldn’t find a leak.

When the light went off one day I went trade the truck in.

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