Loss of power - turbo problem?

[rogerwwebb]

On the second day of a trip from Iowa to North Carolina before Christmas and
during very freezing temperatures our coach began losing power during
acceleration from lower gears and while climbing hills in top gear.

The lose of power is severe and I can feel the drop off and see on the turbo
boost gage drop 3-5 psi as it engine tries to produce more power. It appears
the turbo boost 'catches' and tries to build again, but it drops off the 3-5 psi
and continues this cycle.

I did not get any lights/codes, so I'm unsure what it is. On the flat where
turbo boost is not `in demand' it cruises along fine.

Any ideas, experiences or suggestions where to look first would be appreciated

Roger Webb
91WLWB
Cedar Rapids, IA