So I've been traveling too and from school in another city for the last while and its a 3 hour drive away and I've been noticing that after a little road time if I hammer on the throttle in 5th or 6th gear to pass someone my boost will fly up to about 20-25psi then kind of get stuck there and flutter up and down for a second then climb up to about 40psi, I get no excessive smoke, no strange sounds, and if I'm in a lower gear and not at highway speeds it seems to be perfectly smooth and from what I can tell the turbo seems to be in good shape just wondering if anyone out there has had a similar problem or has any suggestions on what it could be.

 

Waste gate actuator maybe. What turbo is it?

 

Its just the stock he351 not a vgt