Arosa 1.0 MPi - rough cold idle

[redarosa]

I have a 1999 arosa 1.0 MPi with only 29K miles on the clock. The car is kep very well serviced (by me) and has all new plugs, filters, oil, etc. the problem is that it suffers from a very rough idle when cold - although its really sweet when warm. The exhaust pipe is coated in black soot which tells me it's running rich and its got that 'smell' of rich fumes when very cold. Also it idles when stone cold @ 800 rpm - same as when hot - could it be the engine temp sensor ??
Any ideas anyone ??? :confused:

[jose]

These engines give problems only of an evil adjustment of the revolutions because of the dirt in the injection.