Catalytic converter blockage symptoms

Catalytic converter blockage symptoms... I received a P0420 code in which I replaced the first O2 sensor… Code came back on… I took a temperature gun and took readings Before the catalytic converter (325°) and after the catalytic converter (295°). Could this mean that the catalytic converter is indeed blocked up?

 

It was not on the heat shield it was on the pipe before and after the catalytic converter

 

I had a p0420 code about a year ago. I bought two brand new Magnaflow cats and two new sensors for my ‘03. I could only install one cat due to my newly installed TRD headers not allowing me to install the fwd cat(y-pipe dips to low.) I left one of the old cats in, installed the rear Magnaflow cat with the 2 brand new sensors and the code came back after a few months. OEM is just too expensive. I may try Scotty’s method and see if It’ll clear. (Cleaning the cat, not the laquer thinner method)
https://youtu.be/5icTmYItwiE

If not, I’ll just delete the cats, buy the 02 sensor simulator from URD and call it a day.
https://www.urdusa.com/urd-rear-o2-simulator-5vz-fe-3-4l-v6/

 

should be hotter after the cat than before so if you readings are accurate your cat is not doings its job. I am testing the O2 sensor eliminator atm and so far so good. The PCM is looking for a certian waveform and frequency via the O2 sensor(s) and if you truck has 2 O2 sensors, one before the cat and one after the cat and the signal(s) are identicle enough, the cat is not working, hence the code. How a single OS2 sensor system works... havent figured that one out.

 

Holy shit, is this real?! Sounds insane.

 

That's odd...I have TRD headers too and had front/rear Magnaflow cats installed back in 2017, no issues. I didn't install them though, an exhaust shop did.

 

Yeah, guy showed me the new cat vs the oem one and it wasn’t an exact match. That elbow turn was a bit longer. Not much but just enough to hit that cross member

 

I got magnaflow cats. They lasted a few years and back to po420. Urd simulator all the way

 

Magnaflow is probably the best aftermarket brand to get but they will still pale in comparison to OEM Toyota cats in terms of longevity. But I suppose that's why they're 1/3 the price lol.

Mine are going on strong 3 years later, hopefully they make it past my next smog check.

 

The biggest sign would be loss of power (especially if it seems to stall out at a certain RPM) and a flashing check engine light.

 

Still on my original OEM cat at 630,000 miles, just did my smog test last week

 

I did a VERY scientific test while my cat and muffler are both off. I took a leaf blower and blew it in one end of the cat. Airflow coming out was about 50% of what was going in. Did the same with the muffler (with both long pipes on either end still attached) and there seemed to be little-to-no difference. Can I assume that my cat is clogged?

Reason the cat is currently off; I just did some repairs because of P0420, overheating, and power loss (exhaust manifold, water pump, thermo, and fan clutch). Overheating is fixed but power loss (after driving for 10-15 minutes) is not.