Ford Mondeo 2002 TDDI loosing go!

Hey all, its been a long time since i posted last.

I am I need of some advice, the old fatihful seems to be down a lot on power and is struggling to pull on the motorway.

She can still move along but if a hill is put in front of her she just feels like no more to give, i find myself having to change from 5th down to forth and keep it there till the hill goes.

never seemed to have this problem before.

My first guess is a split turbo hose, but i cannot hear any obvious hissing.

She has always had a bit of a flat spot between 2400 and 2600 revs but this is intermittent, no all the time.

I do find when im driving down the road if i lift my foot up slightly on the accelerator pedal that she seems to find a little more go but no where near what it has been.

Any ideas before i rip into the guts and remove all turbo pipes to see if i can locate a split hose

Cheers Matt