I have the same engine, and the same year.
I took my turbo off this winter to have it looks over. My variable vane was very sticky.
I would suggest calling Fair Valley Performance in Sauk City, WI. 608-643-0200. They will be happy to ck it over for you. That is not a cheap turbo, so having yours run through the shop would be a good thing.
I run Cen-Pe-Co Diesel Max fuel additive all the time as well now and you will pick up a very small amount of HP and fuel mileage. But more importantly will lube the pintel in the injectior and have a cleaner burn and less carbon to make the vane stick.
2005 Monaco Dynasty Diamond IV.