[fast924S]

Im not too experenced with the "HIGH MILLAGE" motors oils. Personally I dont like Valvaline, I had lots of problems with it in a 87 VW Jetta I had. I dont see what makes a HIGH MILLAGE oil better, maybe a different additive package. I like Mobil 1 full synthetic, I run it in everything I have.
OverKill, I has seen many motors with build up in the throttle body and intake runners, from mild to heavy, I would think that your isn that bad, But anything that is really really thick, and binding up components should be cleaned. The build up is from engine vapors, oil, and some blow by, that is vented back into the intake threw the PCV valve. But Like I said before run the F/A kit and take wire brush and clean out the throttle body. Also you might want to run the F/A kit before you change the plugs sine it tends to make some build up on the spark plugs.