P0420 AND Rich A/F

[SnowLizard]

I'm searching, even raised a few old threads... so here's a new thread...

Yes I have the P0420, I think it's cats..

I have replaced:
MAF (dif code)
front o2
rear o2
fuel filter
air filter
ISR (don't think it would affect it)
PCV + gromet
Ran seafoam in tank


with all that I now have the notorious p0420... BUT

I also got my A/F to show on my SGII, and I'm running/reading 11.3 startup and 12.4 after warmed up, I'm seeing on heavy acceleration 13.9 MAX, all of which is VERY rich... should be 14.7, yes I have bad smell out the exhaust, but not rotten eggs.

so it's possible that something else is wrong...
yes already replaced front/rear A/F and O2 sensors (99 limited CA emissions)

anyone else able to chime in?

I have 'knocked' on the cat's, and they don't make 'extra' noises (no absolute signs that they are loose) but doesn't mean they aren't bad... just thought I'd ask before replacing cats...

I'm leaning towards the Eastern Catalytic 650511 (front) and 651569 (rear) from rock auto as they are CARB approved and bolt in... oh and not the OEM price tag.

but the rich A/F has me thinking it 'could' be something else... what do you all think?

 

[AZBub]

I had that code when I bought my 4Runner and ended up having to replace the cat.

I recently noticed has smell and high idle. replaced plugs which helped other issues. What was the real problem was the throttle body intake elbow had cracks allowing air in.

now I idle at 700 instead of 1k-1.3k