I have recently re-built the top end of the engine in my Cav Turbo.
New head, New turbo, New gaskets, rollers, belts etc.
At the same time I added a dump valve, boost gauge and a k'N induction kit.
After a "driving it steady period", it now seems to have a bit of a flat spot when driven hard half way through the revs.
Its most noticable when changing from 2nd to 3rd when booting it, it just hesitates and doesn't seem to pull as hard as it used to.
According to the boost gauge its boosting correctly, about 6-8PSI normal and 12-14PSI on over boost. Holds its boost ok.
Anyone have any ideas why? Is there anything obvious I can check?
Any help appreciated.
Check the vacuum hoses first.
did you disable the recirc valve with the spacer?