Intermitent cutting out of engine (Xantia 1.8 16v)

[calywal]

Hi
Wonder if anyone can help ?
My Xantia 1.8 16v has started to intermitently cut out.On slowing down at lights or junction or turning corners the revs drop to zero and the engine cuts out !
It will start again but almost immediatley cuts out again unless I rev the engine hard.
I have been told that it might be the Magnetti Marelli stepper motor which controls the idle speed of the engine...
Has anyone had experience of this problem at all. It happened once before over a year ago but seemed to 'fix itself'
This component is pretty expensive for the size of it and I want to be as sure as possible that it is at fault before I go ahead and buy one.
Many thanks for any help you can offer.
Mike