Peugeot 407 SW 2.0 litre HDi - Throttle Resistance - fredthefifth

Don't hit it very often (honest) but at about two thirds of the way to the floor there is a resistance that requires a definate effort to get past.

Not sure what is going on, is it a performance thing, an economy thing, or a fault?

Any advice please?

Ta, FTF.