gingerish

hi thanks for looking i have a 96 p reg sub impreza wrx wagon and need help
my car was converted from auto transmission to manual previous to me owning car. the car is perfect to drive but i have a problem with the boost. i have changed the actuator with breifly cured for an hour or so but what i get is a drop in boost pressure whilst driving i feel the boost cut down. its not like boodt cut i drops grudual no jerking... i have had a look at the ecu n its a 1ic im not sure if the auto ecu is the same as a manual or even if it has been changed when converted so this may b a factor in the boost problem. any help or knowledge is appreciated thankyou. i have checked all pipes n tested boost solenoid all seems fine, changed plugs too but the engine is sweet sounding, thankyou