A.t.p

I am experiencing a bit rough idle when cold and a very uneven idle when the car is warmed up. Idling at 950 rpm it suddenly goes up to 1500 and down again, or it will stay at 1500 rpm until I touches the throttle. I have tried unplugging the plug on the auxiliary air valve and when I do that the idle becomes much more smooth and the hunting stops. So I suspect the aux valve to be the problem? Any thoughts?

if it’s the aux, I’ve read that they are not available anymore, but that it might help cleaning it. But if cleaning it doesn’t help, what am I supposed to do?

cheers.

Rusty85

It sounds like similar symptoms to an air leak. Slightly rich idle mixture and add a bit more air and the revs rise.
Assuming the aux air valve lets extra air in on start-up and the connection removed is electrical, it sounds like it is letting air in when it shouldn't. Disconnecting the electrics putting it right suggests that something is erratically telling it to open when it shouldn't.
I am sure many would know more than me, but without their input, I suggest looking at whatever temperature sensor 'drives' the aux air valve. That might be the main coolant sensor, more probably one on the induction system. A dirty corroded connection would be nice to find?