Smoke from exhaust, advice please

Hi I'm looking for some advice to a problem I have with my a4 2.0 tdi(170) sline avant 2008 (owned for 3 months) 60 k miles. I was advised by Audi when my car was in for a winter health check that there was excessive smoke coming from exhaust( blue)
they diagnosed the problem as a faulty turbo. I then took the car to 2 other garages for second and third opinions. Both the other garages ( independent Audi specialists) checked out the turbo bearings and impeller play etc.and scanned for boost faults confirmed my turbo was fine( they both even checked inter coolers)
i booked the car into one of the Indy garages to investigate further the smoke issue. They had the car overnight to monitor from cold start including monitoring the injector compensations from cold to full temp.
They advised the following from cold start no smoke from exhaust and normal injector readings, as temp reached 50 deg slight rough idle and blue smoke from exhaust. They injector compensate values almost out of acceptable range . If car revved puff of blue smoke. As car reaches 65-70 deg the injector readings dropping and smoke clearing by 80 deg injector compensate readings all back to normal and no smoke from exhaust and idling perfectly.
i seem to have a blip between 50 and 80 deg where car runs rough and blue smoke from exhaust out side of this temp car runs and starts perfectly. Could this be a software glitch. Any help would be greatly appreciated.
Hopefully an Audi guru will be able to through some light on matter.
cheers

I'm beginning to think injector problem, as the vehicle doesn't seam to consume excessive oil and high injector compensate reading between 50-70 deg engine temp. The injectors were all replaced under the recall in 2011
Is there any way of getting to the bottom of this?

The other thought I had is could it be a faulty pcv valve

Darren198712 said:

I have this on my car. I am still testing it at the moment. Remove top hose on top of the rocker cover and inlet pipe to the turbo (in between the maf and turbo). Blank off the pipe with a Audi wheel nut cap (round locking one works best) and put a breather filter on the rocker cover. I am still testing this as I thought I blown my turbo as I only replaced it last year. It just burns oil and it had been even after the turbo change. So it must of been something else

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Let us know if this works, I will give it a try. Thanks for the advise. Did your smoke go away when engine reached temp. Mine is fine when engine is first started it only occurs briefly when engine partly warmed up

Could this be down to a faulty temperature sensor causing over fuelling whilst the car is warming up?