I do a couple of WOTs every 3-4 days. To where no black stuff comes out.

Oil consumption ~ 2 qt per 7500 Miles.

EGR Code--P0404
I had been getting an EGR code sporadically, so I cleaned the EGR valve. Days after cleaning it squeaky clean, I got the code again... and again.

TEC: Top Engine Cleaner --Service Bulletin
I did the carbon cleaning service with Top Engine Cleaner, as posted by eldorado1 the one involving spraying TEC through the PCV vacuum line.

Next morning, I fired her up and indeed two 4 story tall buildings worth of white smoke came out.

Got an oil change.

Did some WOTs with 2nd gear engine braking, as published on the Technical Archive link above. Exhaust completely clean, and engine sounds "cleaner" or more "mechanical."

this past weekend I did a 750 mile round trip and there was absolutely no oil consumption. Usually after a long trip with a half-dozen WOTs, I would lose 1/2 qt or more. This time--nothing.

I wonder if WOT is sometimes not enough? Oh I'm sure it helps.

I don't want to jinx myself, but I haven't had to go back and re-clean the EGR valve. The code stopped showing up after the TEC.