Running / idle issue

[photosolo]

Apologies if this is a common question.
I'm having idle/ running issues with my 2.1i
It seems to be down to a faulty idle controller - the little black box behind offside
Light cluster.
Is this a common fault ?
I can't find a spare replacement unit anywhere ?
Is there a modification that people advice?
Will this be the sort of issue that installing Megasquirt would rectify?
Any advice would be much appreciated.
Cheers
Dan

[Mocki]

assuming you have checked and replaced as needed the vacume pipes, and the earthing points in the engine bay and cleaned the ecu plugs.

[photosolo]

Yeah all checked!