Vectra, cold low idle surge? - Cyrill666 {P}

Vectra 1999, 2.0 Di.

I\'ve had a number of problems (all minor) recently and they all turned out to be cured with a new airflow sensor (suprise, suprise!). This was fitted a little over a month ago and the car really is 200% better than it was - it\'s amazing what you get used to isn\'t it?

Anyway, recently - the last week or so - I\'ve noticed that during the first mile or so starting from cold, when holding a constant speed (30mph) the engine *sounds* as though it\'s surging once every second or so - not by much, but the change in engine tone is definitely there. I say *sounds* because that\'s the only symptom - the car doesn\'t actually physically surge, or not that I can tell - it just sounds as though it does. At higher speeds the engine seems fine and once warmed up it\'s ok at lower speeds to, so I\'m at a loss.

I\'m not particularly worried at the moment, just interested to find out what may be causing it.

Kind regards,

Value my car