I've been looking fairly intently into this topic since my MKT is approaching 90k. I've taken a look at my intake ports with a $20 Amazon scope. They have a significant amount of build up. I'm going to clean the intake manifold, throttle body, and intake ports. I've looked at the various options:
Intake Chemical Clean
Manual Clean
Of the two, Manual seems to be the safest for the bottom end/turbos. In looking at the Manual cleaning, the safest/fastest of those looks to be the "BMW" Walnut Blasting service for their Direct Injection engines.
Have a look here for DIY instructions on a $800-1000 service:
http://www.bimmerhelp.info/DIY_N54_Valve_Blast.htmlWith all the part/tool purchases it looks to cost 400-500 if you don't have a compressor, or less if you do. The question is does their vacuum adapter fit our intake ports. I've contacted the guy who created the guide above to get his opinion. Anyone know the intake port dimensions?
Many people say that this engine or that engine are better or worse at having or alleviating deposits. There are too many variables to say for sure. Including the fact that many parts are sourced globally from the same manufactures, and PCV systems are pretty universally badly designed on turbo/DI cars. I think a Catch Can will also be purchased with the tools to clean the upper intake.