Bought a TL from a used dealership. 31 days after pulling off the lot, I get a P0420. Great. Didn't have cash at the time to replace much of anything before my first emissions test, so I put O2 sensor spacers on just so I can pass and get tags. The other day my engine starts bogging down. Feels like I'm towing something uphill and losing power. After a few minutes, the engine dies and won't start again. I am able to get the car home by removing the front cat O2 sensor so the engine can breathe. Thinking it's the 3rd cat that's plugged up, I remove it and replace with a pipe. While removing the 3rd cat, a good bit of debris pours out of the front end of it, leading me to think that one of the pre-cats broke apart and got clogged in the 3rd cat. Start the car again, it runs fine for 20 minutes, then dies again the same way. Gets down to idle RPMs then the engine dies. Won't start without the O2 sensor removed. Is it safe to assume that my problem is a bad bank 1 catalytic converter and that replacing that will get the car running again? It makes sense to me, but I want to be confident before dropping a couple hundred more on a cat if I don't need one. My second thought would be something air intake related, as I've been getting a rough idle as well for a little while.

Thanks

 

sounds like a clogged cat to me 3rd cat doesn't have an o2 sensor on it so replacing it wouldn't make sense. (it wouldn't have thrown the P0420) Pull and inspect!

 

Ok. Just tried driving the car 5 miles home with an unplugged O2 sensor and I got 4 miles in before hearing a popping noise, the engine dying, and the VSA light coming on. Won't crank now. Any ideas?

 

I had a similar problem, sold the car as is needing engine. I just got a new TL so didnt bother with it too much. Just started pinging out of no where. And after the next drive i lost power and engine wouldn't turn. Put on a new battery and got her started but it was running rough and died. Maybe one of my cats clogged. I had the p0420 for 3 years on and off.

 

I have a 2011 acura tsx and just recently this morning( very cold weather) i got my engine lights on and got a code P0420. not sure what to do, any suggestion? I was told it could be due to the cold weather, maybe the car didn't warmup well.... or might the sensors.....( what sensors?)

How long can i drive the my car with this problem? even if i removed the the engine lights..

But i did some researched and it could be the catalytic or 02 sensors? if so, where can i get the catalytic?

please help .. thank you!

 

I'd first erase the code and see if it returns. If so probably bad cat. You can check the pre and post O2 sensor activity to see if the cat is indeed in need of replacement.
You can drive the car forever unless the cat decides to go south and disintegrate, not likely. Might want to look into spark plug non fouler as they work well.