I went to my friends garage today and helped him clean the manifold and inlet valves. We checked the intercooler pipes and the inlet pipe on the throttle bottle and there was only the slightest hint of a smear of oil, so just gave them a wipe down.
The inlet valves and little aerofoil like pieces were absolutely caked in sh!t, as were the ends of the injectors. After two hours of taking apart, cleaning with carb cleaner and a toothbrush and putting back together, we were done.
It has completely sorted the rough idle problem I was encountering and the car is a lot smoother at low speeds. I can categorically say that there are no performance gains to speak of. I'm bowled over by just how much sh!t came off the offending items and feel a lot happier with them cleaned. I just can't believe that the TFSI engine continues to run with any assemblance of order with filthy 'coked up' valves and manifold such as I witnessed today.
Here's some photos of the work carried out....
Also finally managed to get my factory engine cover fitted to incorporate the aftermarket cold air induction system. Makes the engine bay look a bit tidier and quietens down those damn noisy injectors!