Big K

Ive been having a boosting problem in the sense that on hard accelaration, the car boost upto about 17psi and then the pressure fades away and then comes back on. It is like putting your foot onto the accelarator, taking it off and then putting it back on. My car is a impreza 2000 turbo my00 with full decat and green cotton panel filter.

I have been told that the car needs a re-map. Any other options? I have also tried resetting the ecu and that didn't seem to work.

Many thanks

Kieron