P0420- Cat is dead, need a plan of action

Hi all,
I’ve been troubleshooting (I mean, sitting on) a problem with my cat for awhile now. I’m running a ‘07 Prius with 300k miles on the original engine. I’ve had a check engine for awhile now, ran Techstream and discovered it was the P0420 code but decided to sit on it as running CataClean and seafoam only made the issue disappear temporarily. I know that due to the amount of miles on my engine, it’s begun burning oil more than it should, making this issue worse, and sure enough I lost acceleration on the highway today, giving me the triangle of death.
(Mid post update, I just grabbed my computer to run Techstream again to check my DTC’s, and it’s gone now? I’m so confused at this point.)
I got to about 45 MPH, felt the car hitting high RPM’s but I wasn’t getting any acceleration, it kinda ‘kicked’ (which is something it’s been doing when city driving recently as well) and I lost all power and got the triangle of death. I believe this is due to the substrate getting caught in the way of the exhaust (I have a loud rattling sound that can often be heard as well) and back pressure causing the engine to shut down, prompting the triangle of death. The car is still driveable and all signs point to the cat being the problematic party. Any ideas for the best way to go about this?

Can I drive the car temporarily without having the cat/exhaust attached to the engine? Should I temporarily cut out the cat until a replacement is ordered? And does anyone have recommendations for non-OEM cats to buy? Simply because I have 300k miles, I’ve been looking at a $100 one on Amazon as it’s cheap and I know spending much money on this is stupid if I don’t have the oil burning issue resolved too.

 

Interesting. I’ve never heard that that rattle could be a misfire, only the thought it was the substrate that had come loose.

On your note regarding scan tools- is Techstream not a capable scan tool? Afaik, thst program is the crème of the crop for checking ECU’s on a Prius. Am I misinformed?

If I am misinformed, then absolutely I agree that gathering more info to solve this issue better is worth it. I was just under the impression that Techstream met that caliber of quality for troubleshooting.

 

haha St. Louis definitely has a market for Prius cats, that’s for sure.
As for the product you suggested, that looks much more reliable than what I was lookin at! Thank you, I’ll look into this a little further.

 

I’ve noticed on Rock Auto specifically that there is a section for OEM and for Aftermarket cats for my year Prius. Any recommendation as to which one I should consider of higher quality? They’re similarly priced, which is why I ask.

 

Thanks for the recommendation! I’ll definitely be looking at that O2 sensor.

does this one guaranteed clear the codes as well? That’s what I’m most curious about with these aftermarket cats.