1996 850 wagon turbo rough idle and check engine light on

I drive a 2008 VE SSV 6LT Commodore Sports Wagon
I have current issue with Engine runs rough, Engine light ON. Traction Control Off
I have checked, plugs and leads which were replace September 2013 and swapped them also with identical car to no resolve

what A4, lots made.
see here for list
http://en.wikipedia.org/wiki/Audi_A4#A4_TDI_concept_e_.282008.29

it's a complex car, all are ofter 2007 and for sure Turbo's
as such can be very hard to work on , and diagnose.
noise and rough idle.
noise is a hands on deal, no net bunny here can guess. that.
but rough idle
that is called misfire.
if a diesel misfires , we check compression first.
the injection rates.
some times just looking at live SCAN data you can see a problem.
my advice find a good German mechanic.
no country stated, making all answer near useless. (oh shock of that)
in my shop i can see you, the car, and the tavern across the street
called Nunavut nook.
a clue. there.huh?
in USA Audio or any ASE certified shop.
or if USA< try alldata dot com.

Compression check may tell you something.

get the car scanned to find the code. many autoparts stores will scan the car for you or you can buy the bluetooth tool that connects to a phone or tablet that has bluetooth. i suspect your spark plugs might be the issue.

1 you need to get the code. 2 sounds like the catalitic converter is bad. If the code was for the exhaust sensor, the catalitic converter will pop this code.

u should definitely get ur engines computer system scanned to avoid misdiagnosing ur isssue. once u retrieve ur eng codes u can then begin to decide which one of ur 25 sensors are acting up, or where to start lookin an testing for ur fault..... good luck

Take it to Auto Zone or Advance Auto and ask them to pull the engine fault code using an OBDII scanner tool. There really isn't enough information to even guess at what the problem MIGHT be. 4-cyl? 6-cyl? Turbo charged? Mileage?

Have you checked the timing, fuel pressure, vacuum hoses, and the Idle Air Control Motor?

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

dont drive make sure you get the timeing belt put on buy a good repair place. one that wont burn you up belt might be 60 bucks but that engine is 2000.00 used . the worst option is that it might need turbo is there smoke . or rough idle comeing from turbo blade will make a nose if it is going out start and listen to turbo if it coming from there turbo . i should have one used for about 300.00 plus shipping [email protected]