Another weird idle problem (1.1 hfx engine)

[vtsboom]

Been looking at an intermittent misfire/hunting problem on the mrs 1.1, it starts and runs fine from cold, once warm though it will misfire/hunt with the revs fluctuating between 700-1000 rpm, but never any higher??, revs will also bounce slightly when just off throttle and then settle again within a few seconds

THe weird thing with it is that if you 'load up' the electrical demands this will stop, lights on full, radio on, heater on max (regardless of heater temp setting) and the revs return to the normal 800 ish rpm, turn any one of these off again and the revs fluctuate. Have checked battery and alternator voltages/outputs and these seem normal.

So far i've checked, cleaned and replaced the icv, carried out a sniff test on coolant and a compression test and these are normal, replaced spark plugs and coil pack, i've been reading through various other threads on here and online in general but haven't been able to find anything conclusive.

Other than this the car runs fine and revs cleanly, any help would be greatly appreciated