cdti lacks power when cold, & engine light on

[mr_dog]

Hi,
Wondering if anyone can offer any advice with my Vectra C (2005 1.9 cdti 120 bhp)
The car lacks power when cold
It starts and idles fine from cold, but as soon as I drive off the car judders and severly lacks power, and the engine light intermittently comes on (usually it is on all the time but sometimes not, and stays on once the car is warm), the car manual says that this is something to do with emissions control?
Once warm the car drives absolutley fine. It also drvies fine if it is restarted when warm.
Stuff I have checked so far:
I have tried unplugging th maf sensor, which makes the car even slower, so I assume this is working fine.
I can hear the turbo whistling whilst driving so I don't think it has seized.
I have taken off the egr valve and it was pretty clean.
The car has recently (a few days ago) had a new thermostat and sender.
Is there anything else I should check?
Is there something specific that controls fuel delivery or boost when the car is cold that doesn't when warm?
Thanks in advance

[lesj]

Check the hoses from the vac pump to the 'valve' on the radiator slam panel. Run your finger along them if they are leaking then you will get a black finger.

[mr_dog]

Thanks, I looked at the piping and although there were no leaks, one end is begining to break up.

The engine problem is now solved - although the egr valve was clean, furthr testing showed the solenoid wasn't working at all, so the valve was never opening, and I got an op com which also threw up a faulty egr.
I have now replaced the egr valve and the car runs fine.

Strange though, almost counter-intuitive - I always thought that if the egr failed in the closed position (effectivey the same as blanking it off), then the egnine would run smoother and power / fuel economy would improve slightly?

Anyway, hope this helps someone in the future...