S8 D2 - Rattle from front exhaust, louder note, down on power, Engine warning light..

[Mcdarcy]

Hi guys

Recently bought a 2001 S8 facelift in Silver! I've put a good few reliable miles on it and loved every moment until this afternoon!!

I noticed a couple of weeks ago after a 400 miles trip back from Scotland that it had developed a horrible rattle at low revs/idle coming from underneath and thought I had traced it to the front section of the exhausts and assumed that it must be a loose heat shield as there seemed to be no other symptoms!

However, this afternoon I noticed that the rattle seems to have gone and been replaced with a far deeper exhaust note. A road test revealed that the car was actually really struggling to rev and was totally unresponsive relative to normal. Initially, it seemed to reluctantly accelerate up but didn't want to go above 5500/6000 and wouldnt make the change in to 5th...... (no comment on the speed achieved). Anyway, a second pass of the dual carriage way revealed the same symptoms but also the yellow engine warning light flashing!

The car now has the light on constantly. It isn't over heating or running rough (other than the exhaust note). The gears change up and down in line with the appropriate speed both in auto and tip modes... I assume it is in Limp mode maybe??

Diagnosis?? Knackered Cats??? Worse??? Help!

Also, I'm new to Audi's, can anyone recommend an independant specialist in North West London??

Thanks

Fraser

[Reffro]

Unfortunately everything you have written is the classic set of symptoms for a failed Catalytic converter. The internals of the cat have broken up and are now blocking the exhaust flow.

[Mcdarcy]

Unfortunately everything you have written is the classic set of symptoms for a failed Catalytic converter. The internals of the cat have broken up and are now blocking the exhaust flow.

Thanks Reffro!!

The unknown is always the tough part!!

Anyone able to suggested a decent garage in NW London??