So, I got three gallons of Purple Power and frankly didn't expect too much from it. I made a plug for the throttle body opening from a plastic bag and some rags. Put a bolt into the MAP grommet and with the ports pointing up it holds precisely a gallon of liquid. Looking into the intake opening there seemed to be a fat cake of carbon gunk stuck to the innards of the IM.

The first gallon of purple power I let sit overnight and it looked like spent motor oil when it came out, unbelievably black and viscous. Looked promising in terms of cleaning power but clearly needed more. So, I drained the first lot and put the second gallon in, which sat soaking for two nights. Drained it this morning and peering in to the intake opening looked quite promising! No more caked on gunk in my field of view. Not bad! On to phase 2.

I had borrowed a Karcher pressure washer from a friend to clean the pavers on my patio (had to fix the pressure switch first but that is a different story! :--) and decided it might just work on the intake manifold to blast out any remaining gunk. I put a work glove over the air intake using quick ties and cut off one finger of the glove to stick the wand in to the IM to avoid it all blowing back on me. Laying it with the ports down in my oil drain tray worked like a charm. A couple of gallons still came out black but after a few more tries it was mostly clear. However, a lot of solid gunk still came out that I could scoop out of the bottom of the drain tray. I went at it with the pressure washer until no more gunk appeared.

I plugged the holes anew and left it soaking with the last gallon of purple power. Tomorrow I will give it another shot with the pressure washer and hope to be done with it. Before bolting it back on the head I will run a borescope through to assure there are no chunks of carbon anywhere in there. I don't want the engine to swallow any large pieces even if they are soft.

In a nutshell, quite impressed by the ability of the Purple Power to dissolve this stuff! In terms of difficulty no more than a 2 of 10 but on the scale of gross and horrible a solid 10!!! :-) More later, will try and shoot a picture of the borescope images if I can.

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2003 4.4i black ext./black int./black headliner (kid's runabout)
2014 535d X-drive, M package, silver/black interior

Sold but not forgotten:
2009 E70 35d, black ext./black int./black headliner (sold 2021)
2006 4.8iS Le Mans blue/cream int./black headliner, SOLD in 2012 sadly...

Other hardware:
2015 Cayenne S (wife's new DD and definitely wroooommmmm)
2016 Tundra 1794 edition crew cab, luxo hauler
2005 Tundra crew cab, weekend hauler. Sold after 150k very happy miles.