peugeot 406 sri turbo (juddery)?

I have always had japanese cars, up until the other night.
I purchased a peugeot 406 sri 2.0 turbo petrol 1996 (p)
It drove fine most the way home then started to notice a vague hesitation whist cruising at 60mph.
the next day i fired her up she ran ok then started to splutter gently, when i rev her she hesitates, the revs drop a few hundred rpm, then she revs up.
the thing is i have noticed this hesitation all the way through the rev range, idle to redline.
I have no idea about these cars can anyone help me?
I had maybe thought dirty sensors, some mucky fuel blocked injectors a little, but im stuck. help!