Slight Idle Issue / Vibration

Hi,

I've just bought an 03 freelander 1.8 petrol which has developed an idle issue, it's not hunting just fluctuating in revs very slightly say ~100 revs, this can be felt as a vibration in the car.

So far I've tried cleaning the throttle housing but this hasn't made any difference, has anyone else had experience of this?

Just an update on the situation with my freelander if anyone fancies offering any advice?

I've found that the car is boiling the water out of the expansion tank.

I have replaced the inlet manifold gasket as I hoped this might solve the idle issue which has developed further to the car refusing to idle at all occasionally and simply cutting out.

I did intend on replacing the thermostat in the hope of solving the boiling water issue and read on these forums about the mod kit, but looking in the engine bay of my car it looks like it may have already been done, could someone clarify if the thermostat housing is positioned to the front right of the engine when fitted please?

Any advise on any of this would be brilliant.

Thanks