boost drops off unexpectedly

[wiener]

Did some minor mods on my pump(fuel screw etc),disabled the governor added a fresh air intake,have pyrometer   and boost gauge.
the boost occasionally will hit 25lbs.(but often only 15 lbs.boost) and usually drops back to 10 lbs.
I have played with the waste gate and even disabled it with no positive results.
Do I need a bigger turbo? Am running a stock turbo on my 94 AAZ Jetta and planning to upgrade any suggestions as to replacement turbos? FMIC coming soon also.

[hairyuk]

could be your wastegate

[wiener]

 played with and disabled  wastegate and it didn't help

[RabbitJockey]

which turbo do you have?  kkk turbos are alot of sticky wastegate valve issues, could also be an exhaust manifold or intake leak