turbo issues please help

hi there i have a 300tdi defender 90 and its just started loosing power at certain revs in each gear it make a funny noise from the turbo then seams like i have no turbo and is just a desil almost as if its hitting a limiter didn't think it had one just seams as though the turbo switches itself of altogether change gear or let of the pedal and got boost back the only mod to my defender engine wise is a rear mounted snorkel and ideas or suggestions would be great thanks Dan

check hoses arent split on pressure side and collapsing on suction side

check your waste-gate actuator aswel, the spring may have weakened.

Turns out wasnt turbo filter was full of sand

Nice easy fix then, glad it's sorted!