Hey guys! New to the site hoping you can help...

Hi Emilyann, welcome to ASN where many VAG owners come to hang out, compare ideas and notes, and scratch our heads when VAG dealerships go round in circles spending our cash when they can't sort an issue !!!

The fact it happens in neutral would lead me to think that you have an issue with idle stabilisation. I'm sure the wiring loom issues happened whilst driving, not when sat at idle. Other thing I'm wondering is whether it's fuelling related, has anyone checked glow plugs / fuel pump? What mileage has the car done?

If I am honest you may be better off taking the car to an independent specialist for a check up as they will have more troubleshooting experience and won't just rely on error codes.

Apparently injectors and wiring are being replaced FOC by Audi because this is a known problem

Welcome to Audi life

TBH it sounds like a possible DSG clutch issue to me and as this is stupidly expensive i would read the small print in you warranty very carefully. Good luck and let us know how you get on

paddy said:

Apparently injectors and wiring are being replaced FOC by Audi because this is a known problem

Welcome to Audi life

TBH it sounds like a possible DSG clutch issue to me and as this is stupidly expensive i would read the small print in you warranty very carefully. Good luck and let us know how you get on

Click to expand...

Can DSG produce a misfire. If it had just been judder I would agree, but surely the misfire can only be a result of a fuelling / mix issue?

Well i was taking the view that she was "interpreting" a judder as a misfire. As it only occurs in neutral i wondered whether it might be clutches/flywheel as her starter runs slow as well which could be drag. If its fueling mix then get the injector done and push for good will given the 170 problems but at £800+ a pop you need to be dead sure thats the problem.
As for audi's "suck it and see" philosophy ...be very careful, my 3.2 went in for a diagnosis and the next thing i knew i had a bill for £2.5k and they still hadn't tracked down the fault. At a £1.3 k + a day fault finding can be very expensive if there is no fault code......which makes me wonder, as you Work for VW have you had any fault codes looked at ?
EDIT
Found this that seems to say the wiring issue was post 2005 but seems to be up the rev range.
Taken from Dec issue of Audi Magazine:



"Hidden electrical issues can affect the Audi A3 TDi from 2005 onwards.with individual pump injectors. After covering more than 30k miles, this model can develop a strange but frustrating judder between 3500 and 4200rpm in fourth, fifth and sixth gears. The judder mainly occurs under heavy load and is very noticeable. THe cause of the fault is the electrical contacts on the individual pump injector units within the cylinder head. There is a short wiring loom which travels inside the cylinder head and feeds each PD unit individually. Each PD unit requires a signal and a power feed but, as they are located deep inside the cylinder head, it would be very difficult to connect them to the main wiring loom without this short adaptor loom. The adaptor loom carries all connections for the PD units and is installed when the engine is built. You can see the large, round plug at the rear of the cylinder head, this plug connects it to the rest of the engine bay wiring system.
The fault occurs because the electrical contacts can become weakened by vibration over long periods. They then make and break a contact very rapidly, virtually resonating with the basic vibration that occurs in the engine speed range, In some cases, you may find a recorded fault suggesting open circuit on one or more injectors, but this is not always the case. It is also very difficult to reproduce with a cold engine or with the car stationary.
If you experience this symptom, the only way to check it is to remove the engine cam cover and physically inspect and electrically test these terminals. There is an uprated and modified electrical loom which cures the problem and should prevent it occuring again, Only the upgraded loom is available, so, rest assured, if you replace it you wont get another iffy one. The part number is 03G 971 033D."

Welcome along. When was the car last serviced?? And does it have FSH? Hope you get to the bottom of things, it spoils the pleasure of owning.

I suppose you could get them to check fuel pressure at tickover. It could be a dribbling injector that gets better as revs rise if fuel pressure is rising as well. Most problems like this are reversed and happen under load where as yours is when running light. It seems odd to me that it does it in P and N but i am assuming not stationery in D ? when the clutch is loaded up. It would be interesting to see if VCDS showed up a misfire count and on which cylinders.

EDIT

DMF on the way out
2006 TDI DSG- DMF is toast !!! - YouTube

The only other thought I'm having is air leak. Once you stop accelerating and the turbo goes to vacuum (from boost), if there was an air leak in the induction side this could cause idle fluctuation.

Going back to basics I'd:

1) Have the glow plugs out and check their condition
2) Check around the block for any signs of oil leaks / check inside oil cap for any sign of moisture (mayonnaise coloured build up)
3) Check all air pipes and jubilee clips to make sure no pipes have any wear / splits either from the clips or due to rubbing on anything else
4) Get VAGCOM / VCDS on the car and do a log on the vehicle whilst it running
5) Cross my fingers and hope its nothing to do with the turbo or wastegate!

can you clean throttle bodies on these cars? I know far too little about diesel cars!

Yes i was wondering air leak W...
Also found this

http://www.audi-sport.net/vb/new-a3-s3-sportback-8p-chassis/111630-a3-2-0-tdi-140-judder-vibration-idle-just-had-new-clutch-duel-mass-fly-wheel.html

Not a lot of help but it shows its not unusual...

This is the only other item i could see relating to a 140 golf but same thing

mk5 GT TDI 2.0 140BHP juddering when stopped?????????


Might be a miss fire have the car checked with vagcom for fault codes. then check glow plugs, glow plug wiring loom ( these are well known to crack at the wire entry new ones 08 and after are modified to stop this) if it is a miss fire and it is still juddering check the injector wiring harness this sits under the head and is constantly cooled and heated in the oil and after time breaks down and current is lost or incorrect signal is passed to the injectors if its still miss firing it is an injector $$$
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bottom line as warren says is you need to get it logged to see if you can pin down electric or fuel or mechanical first.

Best of luck; which independent are you using out of curiosity?