159 Cruiser and
AO Silver Member
Join Date: Jul 2012
Location: United Kingdom
It's not really soot, due to the oil that comes in through the inlet, it's much more gunky (if you have removed and cleaned your MAP sensor you will know exactly what it is like!).
A few people have removed the inlet and done some cleaning from that end, but you won't get any of the stuff from the smaller pipes, and large bits can drop off into the cylinders.
My understanding is the best time to do this job is during a cam belt change (as you need to remove this anyway to remove it (as is my understanding)).
159 1.9JTDM Ti and Giulietta 2.0 Veloce
ex: Punto 55s, Golf Mk5 1.4FSi, A3 (8P) Sportback 2.0TDi SE, A4 (B8) 2.0TDI S-Line, 306 HDI Meridian