2007 A4 avant 2.0 Tdi 170 issues

[deeempee]

Car has just come back from main dealer service and MOT with a report of rough idling with tandem pump suspected of being the problem. (and hence oil in fuel, though no issues at all with the emissions tests) Dealer won't commit to the potential cost of the work as I suspect (having searched the forums) the number of potential causes could mean significant work.

Have had my Avant for the last year and with a mixture of commutes and motorway driving have averaged around 39mpg (have been driving reasonably restrained to get it that far eg. 70/75 mph on motorways and no aggressive accelerating). Seems low but similar to other people's comments.

The 'rough idle' is the occasional judder when idling at traffic lights, no dipping of the revs and some days isn't evident at all.

I wouldn't think too much of the symptoms but the computer is now indicating next service in 8500miles (it's variable service interval) which puts it at 9000miles between services, whereas it was managing approx 21000 miles. It's not down to driving habits as my wifes VW passat tdi 140 4 motion does pretty much identical trips and manages over 20000 miles between services if left.

Car has done approx 73000 miles from new (13000 miles since I've had it). Cam belt was changed at 57000 by main dealer.

Any help in what to do/what to investigate much appreciated.

[Plank]

Apparently the tandem pump going is a lot more common on the 140s, which is what happened to mine. Don't know if it'd work on yours but holding the revs up to 1600 made the car judder; although some have said it can do anywhere between 1600-1800. My repair cost about £280 for the pump, few hours labour cleaning the oil out, and £300 each to refurb the injectors (replacing the seals etc). However, if the injectors aren't in need of work it shouldn't be too costly in the grand scheme of things.