It looks like my cat has gone on my A6 Audi V6.

Short version.
Car started misfiring at high revs with a loss of power low down in the rev range.
Changed fuel filter and cleaned the in tank pump. Used Forte injector cleaner in the tank with no change.
Until yesterday when it started behaving. This coincided with a rattle coming from under the passenger side where the cat is.
This was on my things to check.
What are my options regarding repair/replacement on a budget as Audi want £1100 just for the part.

Thanks in advance

Brad

Misfire has killed your CAT I'm afraid, you need to fix the misfire and the CAT.

Misfire was caused by a blockage in the cat and the gasses not escaping.

i got a universal cat from https://www.ebay.co.uk/usr/cats_2_u?_trksid=p2047675.l2559
just had to weld the ends on from my old one and job done...they may do a straight fit one as well.

Don't chuck the old one away, it will have real value as scrap, possibly a few hundred quid!
(our MX5 cat was stolen...)

Be aware repro cats contain a tiny fraction of the important/expensive stuff that the OEM one has, hence the scrap value etc etc. So it may not last long.
Also be away a CAT will not go faulty unless there is a problem elsewhere (99.99% of the time)
Many carts are replaced at MoT time because of emission fail, fit a new cheap cat, passes. Fails teh following year as the root problem has not been fixed. Just so you are aware.... (ie if your cat is blocked, then why?)

I second not binning the old unit, yesterday I saw a Honda Jazz that had been parked on one of the local park and ride sites where some lowlife must have jacked it up and cut off the cat. Parts from Honda over £1500 + VAT

Thanks for the replies fellas.
Well I'm not paying Audi prices and I won't be able to get it from anywhere else.
So my plan is to gut the old one as it's just off the manifold, then fit an inline one on one of the straight runs further down stream and just extend the wiring for the o2 sensor.

I had a Cat break up on an old Rover 416, I took it off, smashed all the bits out, put it back on the car, and it still
passed the MOT without any of the innards

My Mot guy ( a friend) had to coax it through the stages, but it still passed the Mot

steve