2010 2.0TFSI S-Line Avant - Not nice under hard acceleration!

[hopper1]

Hi Guys,
I'm a newbie here, making my first post, so hello all!...
I have a 2.0 TFSI A4 Avant S-Line Quattro (Dec 2010).
All was well until about 9000 miles (1 year).
Exiting a roundabout hard in 2nd gear, changing up quickly to 3rd, then back hard on the throttle and it seems like there's someone in the engine bay, slamming the bulkhead with a sledge hammer! It doesn't disappear, I have to back right off the throttle, then accelerate again (nicely!) ***!
I took an Audi Norwich technician out in it, and demonstrated it to him, then left the vehicle with them for a few days...
Audi answer... Don't change gear so quickly! I was flabbergasted at that. I've owned some right buckets in my life, thrashed them all (at times) and never had one behave like that.
I thought it could be a fuelling issue, but they (who know everything) said all was ok with the car... Basically, it's my fault, for giving it a bit, on occasion!
It now appears to be happing under load (not hard) from 3rd to 4th (not a quick change, either), more subtle thudding though...
HAs anyone else on here come across this, or know the reason.
A salesman I spoke with, new exactly what I was on about, as he'd had it happen to him, he described it as the engine hitting the bulkhead because of the high revs! (he was serious, too)... C'mon, I ask you...:confused:
I'd be greatful of any help on this. The car is now 16 months old, 13,000 miles.

Paul

EDIT: Just been reading through some posts, so I must also point out that the car runs mainly on Tesco unleaded! Is this an epic fail on my part!?

[CeeTee]

Had an A6 and though what you describe is very violent sounding does it feel like the engine is not firing under load, missing almost? with a lack of power once you hit certain rev's? Two garages, a main and an indy swore it was either that the inlet manifold was warped or that the injectors were blocked or failing, no warning lights or diagnostic problems and the fact that it was not a constant issue at all rev's led me to believe that it was a bit more low tech. I would not let any of the garages do expensive investigations or replace expensive parts until they could tell me for sure that it was going to be solved by their "work". It finally cut out on me and would not rev or drive past 2100 rpm. I nursed it to a garage and after insisting not just any available mechanic found the issue I would not let them do anything. In the end it was a blocked fuel filter and lines caused by cheap and dirty fuel from a cheap fuel seller, no additives in the cheap stuff to keep your engine clean I am told. Cost me just the money for a filter as they were so embarrassed about the problem. Moral of the story, cheap fuel is a false economy.
Change your filter, put in some decent fuel and add some cleaner to the tank of fuel and give her an "Italian" tune up.

[hopper1]

Had an A6 and though what you describe is very violent sounding does it feel like the engine is not firing under load, missing almost? with a lack of power once you hit certain rev's? Two garages, a main and an indy swore it was either that the inlet manifold was warped or that the injectors were blocked or failing, no warning lights or diagnostic problems and the fact that it was not a constant issue at all rev's led me to believe that it was a bit more low tech. I would not let any of the garages do expensive investigations or replace expensive parts until they could tell me for sure that it was going to be solved by their "work". It finally cut out on me and would not rev or drive past 2100 rpm. I nursed it to a garage and after insisting not just any available mechanic found the issue I would not let them do anything. In the end it was a blocked fuel filter and lines caused by cheap and dirty fuel from a cheap fuel seller, no additives in the cheap stuff to keep your engine clean I am told. Cost me just the money for a filter as they were so embarrassed about the problem. Moral of the story, cheap fuel is a false economy.
Change your filter, put in some decent fuel and add some cleaner to the tank of fuel and give her an "Italian" tune up.

When it first happened, I likened it to a motorbike hitting the rev limiter, and I knew my revs were high (but not exactly watching them). No limiter on the Audi, though. It could be a misfire type issue, and under hard acceleration, this would feel more violent (IMO).
I'm going to avoid the supermarket fuels for a while, see if that has an affect...
But, still like to here anymore opinions on here.
Thanks CeeTee.