Like Ed said, a vacuum line closer to the throttle body might help break up sludge in the upper intake manifold a bit better since its more "upstream". The trick with the seafoam is to take the vac line off while the motor is running and plug it with your thumb. Hold the cup of seafoam in your other hand. Use a big cup so you can put your hand in it. Put the tube down to the surface of the seafoam unplug the tube and let some of it suck in. Repeat this by letting it drink a little at a time. the motor bogs or stalls if you let the vacuum line open to suck air for a short period and may cause a maf-related cel (never has for me but I imagine if you let it go for a while like that it might), so keep it plugged and alternate letting it "drink".