Bad cat or 02 sensor?

[Living_Quiet]

I recently had to replace the cylinder 1 fuel injector and all spark plugs because a faulty injector was dumping fuel into my engine.

Before the repair I was told there's a good chance the cat will be shot soon from the problem. Sure enough, a few hundred miles after the fix I got the p0420 code saying my bank 1 cat is no good.

Is there any chance this goes away after driving for a bit since the original problem was fixed? If it's just the 02 sensor being funky

If not, does anyone know what it might cost $$$ to have a dealer replace it?

[fly2hip8]

$600ish. It's $419 just for the cat

[PowertoLove]

There are cat cleaners out there you put in the gas tank. Sometimes just running it hard enough to burn the crap off the inside of the cat fixes it, sometimes nothing fixes it. I ran one of my LS1 cars for over 100k with that code without issue. I just had the light tuned off for that code. Its kinda hinky anyways, the cat is still active working but below a certain threshold that is set very high. A lot of times replacing a OEM cat with a aftermarket cat won't turn off the light because the aftermarket cat isn't efficient enough to meet the threshold level.

[pyroguy]

OEM cats are EXPENSIVE. The dealer will put OEM parts on it so be prepared for an expensive repair bill. You're better off to get either high flow cats or get some long tube headers with or without high flow cats. A direct fit Magnaflow converter from autozone runs $800 for 1! You can get a set of Solo Performance high flow cats for less than that for a pair.

[Greenhornet2]

It's most likely the cat, not the O2. If the Cat is breaking down it is not recommended to drive with it as the pieces of the cat can be sucked back into the combustion chamber and cause damage. If it is blown out and basically a straight pipe then it would run ok, the problem is when it starts to melt and turn into a brick. Leaking fuel injectors is well known to melt down cats.