Williams 2 rough tick over when hot

[Samj1519]

hey,
today i left my willimas ticking over for a while it was ticking over lovely. however as the car warmed up it seem that the rev's started to drop until the car nearly stalled then they would bounce back up again and tick over normal and then again the revs dropped and the car splutterd and nearly stalled and then again the revs bounced back again and it continued to do this.

any idea what may be causing this ? and when it doesn't do it until the car warms up or thats how it seems ?
any help would be greatly appreciated.

[16v_paddy]

There's a long list of things that can cause these fun & games

Dodgy lambda sensor
coolant temp sensor
throttle position sensor
Poor earth connection somewhere - gearbox earth strap & road speed sensor on the back of the clocks are the most common
dirty idle control valve
vacuum/air leak