2009 Vauxhall Astra air/whooshing noise

Recently ive noticed a sort of turbo lag between second and third I thought at first it might the fuel filter but in the last 2 weeks theres an air like whooshing noise that gets louder as the revs go up then as I change gear it sort of releases abit like a dump valve then starts all over as I take the revs up again also when its sitting idle and you rev it up as the revs come back down it sort of goes pu-chu like airs getting stuck somewhere someone said my turbo might be on the way out but apart from the noise its not driving any different or smoking but my mechanic said unless he starts stripping it down he doesn't really have a clue