I have the dreaded P0420 on my 2001 SE Miata even though the car runs perfect. If I understood something I read on a topic regarding spec Miatas, you can remove the rear 02 and zip tie it inside the car (and I assume also that the hole in the exhaust is plugged as well). Apparently this method prevents the CEL from coming on. Is that accurate? Or is it better to get one of those j-style 02 spacers and put that in.
The O2 sensor has a built in heater and gets very hot. Tie it up outside the car, If you must. Possibly a spark plug spacer will cheat the code, will definitely be safer. Actually fixing the problem is also an option 😊
Yeah, I don't have the cash to drop in on a new cat right now, so it would be a temporary fix.
I used the spark plug spacer trick, worked great.
Do you have the cash to buy a new car when you catch it on fire with the heated O2 sensor hitting brush or debris or just melting bits?
Letting it dangle outside of the exhaust stream doesn't eliminate the MIL. Just leave it in the hole it is already in.
If you do an honest read of threads on the spacer approach you won't come away with the conclusion that it "will work". You are in NC; a cheap generic cat is probably all you need to be mostly running again without the light (until it ages out sooner than a proper one). Your car is not running 'just fine' without it, you've just defined 'fine' by throwing out normal criteria. It could be running 'just fine' on two cylinders with that same logic.
-Rich
welcome with just 3 posts. Your in the right place.
If you have a 2001SE stop in and visit
https://forum.miata.net/vb/showthrea...POSTS+REGISTRY
You know that code can have 2 causes. Bad cat or o2 sensor. Have you done all the electrical tests on the sensor. I just needed a new sensor. Anyway, I would leave it installed for two reasons. You won't have to find a plug for the exhaust and leaving that annoying light has a reason. You can ignore it or fix it.