Ok. I had similar issues a few months ago.

I started by disconnecting the CSV. This made no difference. Blue Plug
I then tried disconnecting AAV. Black plug under inlet manifold. This stopped my problem.
So I tried replacing the aux air still no difference. It turned out the earth for the AAV on the wiper motor had worked loose. Cleaned and tightened and all was ok.

Even if you bro's is not an earth I would certaining start here. Also my favourite saying. Try the simples to - Rotor/Sparkers and leads if not new treat the car to a new set.