Bad Idle And Stalling Advice - K Series

My rover 214 cabby has an idle issue. 

When i dip the clutch, when coming to a stop for example, the revs will drop well below idle and it sometimes stalls. Sometimes it catches itself but the idle is rough, fluctuates between 800-1000rpm. 

Now if this was on any car what would you guys suspect? Rover forums are very slow, this is probably the busiest forum i know of so thought id ask here too. 

Ive already cleaned throttle body, checked stepper motor, not 100% sure its working and not sure how to rule it out? or if this would cause the issue? Its had full service before i MOTd it too. Cap, leads, plugs, cambelt, oil, filters, 

If we forget that its a rover K series and it was happening on any other make of car what would the normal things be to check?
If anyone can tell me how to eliminate certain components it would be great. Other than the idle it runs OK, bit of a flatspot but it hasnt been used for 7years soo i put it down to needing some use. 

 

Idle problems are usually down to IACV or LAMBDA. Unplug each one in turn and drive the car. When unplugged the ECU runs on internal default values which eliminate any faulty readings from the equipment.

Will try that thanks…maybe lambda is causing the slightly ‘off’ performance too. 

being a K Series could be the head gasket going, one of the main things to check first

Yeah that thought is in the back of my mind…compression check will be done.

Done my metro headgasket few months ago…dont wanna do another one yet