Hesitation and Blowing noise when warm

[fordy29941]

Hope someone can help.

I have a 2012 mk4 mondeo 2.0 tdci 163. On cold start the car performs fine (a little noisy but otherwise fine) however when the car warms up, I get a little bit of lag/hesitation of power after gear changes and when accelerating and after a second or so it feels like the turbo kicks in and propels the car forward slightly. Also I can hear a blowing noise from the front end, similar to an exhaust noise. (The noise also only occurs when the engine is warm)

Theirs no smoke at all from the exhaust.

I have checked the exhaust front to back and all seems fine (no holes)

Could this be intercooler/boost pipe? i thought maybe the noise is only happening because the pipes have warmed up and become flexible. I haven't had a chance to get under to check it out but just thought I'd ask the question to see if any had experienced the same issue or knows what it could be