Massive misfires and smoke

[Rusty]

Might be worth upgrading your DV to something like Apr r1. That T piece will have been leaking a little boost but the DV will have been short circuiting the turbo, hence the boost reduction.

[UrS4boy]

The first defects have been detected. The blow off valve was completely destroyed and basically wide open.

Those parts are from the Positive Crankcase Ventilation (PCV) system. If you read through this post (linked below), you should find the parts and the part numbers you need:

http://forums.quattroworld.com/s4s6/msgs/22506.phtml

[newsh]

Worth relacing that little one way valve that is in the picture (small black valve 20mm diameter) while you're in there, if the valve doesn't close properly it leaks boost into the breather system. They are prone to failure.

[prj]

Might be worth upgrading your DV to something like Apr r1. That T piece will have been leaking a little boost but the DV will have been short circuiting the turbo, hence the boost reduction.

Disagree. OEM DV is very good and cheap, and as evidenced lasts for 20 years.
When replacing simply replace with 710N from Audi TT.

[newsh]

The valve that's cupped in your hand in this pic.

[Kroegarn]

Finally the car is running properly again. The actual problem was the MAF. Unplugged in and suddenly the car was running a lot better. Removed it and id did´nt look broken, so probably just dirty, changed it for the RS2 version that has been laying on the shelf.

[UrS4boy]

Finally the car is running properly again. The actual problem was the MAF. Unplugged in and suddenly the car was running a lot better. Removed it and id did´nt look broken, so probably just dirty, changed it for the RS2 version that has been laying on the shelf.

I "win": post 8.

You should probably check and/or clean the MAF, and check the six pin (only 5 wire) MAF connector to see if the pins are mating properly (sometimes the female pins in the harness connector get pushed back and away from the MAF male pins. IF the ignition is fine and the spark plugs are fine and your injectors aren't leaking massive amounts of fuel and aren't stuck open, then you are missing air, i.e. boost leak.

1. Check and/or replace the spark plugs.
2. Check MAF
3. Boost leak check.