Steam cleaning the intake
 

I once came across this method of cleaning the intake.

Remove the intake from the throttle body.
With engine warmed up and running, use a spray bottle to squirt water into the throttle body.

Supposedly, the resulting steam will remove deposits. With care, it seems pretty simple and straight forward. You would probably want to use distilled/DI water to avoid mineral build up. I saw a post which said that the carbon flaking off could clog the cat. converter.

Has anyone tried this? Is the cat clogging a real risk, and how big of one? Besides the cat, any other possible risks?

I ran a can of Seafoam through it before changing the spark plugs, but there is still some of the vulcan pingy under heavy load. A Ford TSB calls for using 3 cans of cleaner, but also says to replace the plugs after, because of fouling. So, I'm thinking of giving this a try before the next oil change.

if seafoam doesn't clean it up, I don't think water will. maybe an additional treatment of seafoam? you also have to look at how you're introducing the seafoam... at least in my engine, the best place is the EVAP vacuum hose to the throttle body as any other hoses will introduce it unevenly and the car won't run at all without the intake pipes intact because of the AFM.