Engine power fine when cold, looses umph when hot

[ianad]

When the care is in the first few miles and not fully warmed up the acceleration feels fine, however when it warms up it looses power and the turbo feels like it is doing little. It feels like something is loosing pressure. Any ideas of where to look on the engine or how to test a problem like this? Many Thanks, Ian

[ianad]

http://wikilec.9600.org/index.php/Boost_leak
Looking around I found this method for testing if turbo pipes have a leak
I will warm it up and give it a try.
Thanks JonT