Turbo Problems ('04 Focus Tdci)

[HeyItsSean]

Hey guys, first time posting so I hope it's in the right place.

So my problem is that my turbo decides it wants to stop working, it starts off fine plenty of power and can hear the turbo working, but as soon as I need to open up the throttle or go up a hill the turbo cuts out... But turning off the engine and starting it back up and it's back to normal, for a little while. Also wen it's cut out, it'll sometimes bellow out smoke, but if I power through it til I hit ~3k RPM it'll clear and work again.

I've had advice that it might be the waste gate sticking but I'm not really mechanic savvy.

Any ideas on what it could be?

Cheers.