keep driving with codes, cel=-

[jamesmetairie]

05 base vibe. Had cel engine light for a very long time. the usual 0171 and 420.

It is not a problem here to do with emissions check.
But I am curious=- Is there any sure damage happening . Should I knock my head on the wall and start buying parts?
I changed the MAF today with Denso from Amazon. The cel is still on.

I will go to auto zone and see what the gadget says.

[jamesmetairie]

gadget said code 0420.

[jolt]

Here is link with more info about that code, and note that the Vibe is a Toyota drive train:

https://www.autocodes.com/p0420_toyota.html

Toyota & Nissan

The most common cause for P0420 in Toyota and Nissan cars is a bad catalytic converter. You should also ensure your engine is not burning motor oil.

Check for vacuum leaks and exhaust leaks first. Then check to see if you notice any blue smoke coming from the exhaust pipe. Blue smoke coming from the exhaust pipe is a sign that you might have an issue with the crankcase ventilation, or even something as bad as a damaged turbocharger or bad piston rings.

If you do not notice any blue smoke at any RPM, it is most likely that your catalytic converter is worn out. You may find similar issues on Nissan cars.

This is a common code for these cars with higher mileage. If you dig through this web site, you can find some work a rounds to this issue. If you want a true fix to the problem, most people have to buy a new cat, but the cat will go bad fast if the engine burns oil. If your engine uses oil, do not waste money on a new cat. The cat can plug up from the oil if you keep driving it but that is about the only damage that you will do, unless you run the engine out of oil, because it burned the oil up, then you will blow the engine up. So rebuild the engine and put a new factory cat on it and the code will go away. Is the car worth it? Most likely not. So just drive it and keep it full of oil. After all, nothing last forever.

[joatmon]

The P0420 is likely a bad cat. I used some spark plug antifoulers to trick the system to not throw the CEL, so that I'd be able to see if a different code came up.

The P0171 is engine too lean. A not uncommon problem with the 1ZZs is the intake manifold gasket leaking, allowing more air in that the MAF measures.