I was able to get 63 mpg on one run when I first got it (at 3 years old, 93000 miles).
It started to get difficult to start at 100,000 miles and economy went down from 50mpg to 35mpg. The injectors were diagnosed as cracked (a common problem at 100,000 miles)
All were replaced and everything fine but economy still 35mpg. I put a mild plug in superchip on it and can now get 40mpg.
Any ideas? Pump not delivering as much pressure?

If you have superchiped the ecu, it will increase the fuel used as it is trying to get more power from the engine. My advice would be that if you are looking to get fuel economy out of the engine de-tune the ecu.
Ja.

A lot of these common-rail high pressure Diesels do tend to lose their performance at about 100,000 miles, due to wear in the pump and gunk forming in all the pipes and injectors. Obviously this hurts the economy as well. It's a common fault which can be quite pricey to get fixed, as all that high tech stuff in cars usually is.
A mate of mine who works in a Glasgow VW garage jokes about the fact that a Golf TDi 130 becomes a Golf TDi 110 after about 70-80 thousand miles!

63 mpg...you were dreaming.at 190.000it may just be worn out...has a mechanic ever looked at it????