P0431

[KBell]

2006, S4 with 81,000 miles.
Throws this code. Check engine light. Catalytic converter with all the other misfires codes for each cylinder.
Car is sluggish on higher RPM's.

I am the original owner and car has always burned oil. O2 sensors and all maintenance UTD.

I sure it is the PreCats or Catalytic converter.

What are my options before taking to dealer and being quoted a large bill?

Thanks you , Kevin

[KBell]

Done little research.
JHM 'Piggie' down pipes?
Any advice or opinions appreciated.

[jakeoboy67]

you probably have a failing/collapsed cat converter, piggies fix that but is illegal.
if you have emission testing in your state, you'll have some trouble passing.

are the misfires all on 1 bank ? 1-2-3-4 or 5-6-7-8 ?

[KBell]

Both Banks

[draggingto]

My car has the same problem. Haven't really had time to mess with it, so for now it sits in the garage. Let me know if gutting the pre cats fixes your problem.

[1.8t]

Done little research.
JHM 'Piggie' down pipes?
Any advice or opinions appreciated.

Piggies with a tune and you should still be able to pass emissions no problem if you have the OBD test

[AlexS]

in my case with the code P0431 I had oil leak from control housing on the exhaust manifold.
after I fixed it, is gone.

[DylanFulton]

I had a recurring P0431 code, I did piggies and O2 spacers about a month ago and the code hasn't come back since.

[KBell]

Update.
The dealer first changed MAF, O2, etc. Large bill.
Still had same problem. Check engine light and sluggish at higher RPM's.
I mentioned about the PreCats.
We had a meeting --->cleaned preCats --->spacers for o2 sensor--->Codes all clear !
Wow, the power is BACK!

[2004B6S4]

Update.
The dealer first changed MAF, O2, etc. Large bill.
Still had same problem. Check engine light and sluggish at higher RPM's.
I mentioned about the PreCats.
We had a meeting --->cleaned preCats --->spacers for o2 sensor--->Codes all clear !
Wow, the power is BACK!

The dealership did this? I'm not sure what you mean by cleaned, you only need spacers if they were gutted but I'd be amazed if a dealership did that...
Anyways, it's good to hear that another S4 is back on the road working properly!

[KBell]

Yes.
The dealership.
They were kinda frustrated because they were replacing things and the codes kept coming back. Misfire.
Sluggish at higher RPM's. The car would lose breath.
Spent multiple of thousands there on other things, and I was getting a little frustrated.
After a meeting with the Service manager and technician, they decided to do little investigation and reading.
The technician said visually, they looked fine. But after doing some homework, he agreed .

[draggingto]

Well, looks like my car will be going on the lift and having the down pipes removed and gutted here soon. Anyone know the best place to get the O2 spacers?