I want to sort this once and for all.

[Goran]

Originally Posted by Bandycoot

We have success! I have just changed the fuel pressure regulator and bingo! No more lights and it drive like a dream. When I was taking the inlet manifold off the other day I noticed when I disconnected the fuel hose from the regulator to get the fuel rail off there was no pressure and as there was no fuel leaking anywhere I guessed this was the cause of the pressure loss.

I didn't have any idea that this could have been the cause of the problem. Nobody mentioned it at all. Audi were saying all the time it was an air leak which is why I rebuilt the inlet manifold. Anyway, I'm a happy bunny.

Well done! good to hear it was a easy fix. This is definitely one to note down for future reference.
Its rather annoying that Audi in their own maintenance manual don't mention that fault codes on one component (throttle valve in this case) can be caused by a completely different component. I wonder why it didn't show up any injector fault codes considering the fuel pressure was low?

078133534C - its the little bu**er sitting above the fuel rail driver's side, with the little clear plastic pipe attached to it.