2000 isx15 turbo issue

[4x4mama]

So we have 2000 isx15 in a 2001 Freightliner century. We aren't getting full turbo all the time. It had a bad clamp on the exhaust side that we replaced. There's a hose that was pinched off intake side to the waistegate actuator. Undid it and didn't seem to make a difference. Typically getting 20-27 boost in cold temps. In hotter temps 18-20. But it will also just all of a sudden give a burst of boost sometimes in all temps.

Any ideas on what could be going on? Thanks