Sorry to post this here, but I'm not allowed to post in the "how to" section. Maybe a moderator can post this there or maybe make it an addendum to the existing Sea Foam thread.
To add Sea Foam to your engine through the brake booster hose without worrying about killing/re-starting your engine, try this:
Get one of the funnels with a lid and an "open/closed" valve at your local autoparts store, like this one I picked up from Advanced:
It has this handy "open/closed" valve which you can use to control the amount of Sea Foam you put in you engine (sorry this pic is blurry):
It also has a plastic tip on the end that is PERFECT for the brake booster hose to fit onto (this pic is also blurry, but the rest are ok):
Simply remove you brake booster hose and slip it over the plastic tip on the funnel. The funnel tip is long enough to fit in the hose and is tight enough that you don't have to worry about it coming apart. This is important: LEAVE THE VALVE SET TO "CLOSED", and the lid on the funnel, and start your truck.
Your truck will start right up, and idle fine. You will notice the plastic hose from the funnel will collapse.
This is o.k. The lid may also bend in a little as the vacuum from the hose pulls air through the "open/closed" valve, but you can go ahead and remove the lid, your truck will still run fine.
The collapsed hose will prevent the truck from sucking in enough Sea Foam at one time to kill the engine. Remember to leave the valve set to "closed" and pour the amount of Sea Foam you wish to add and watch the truck drink it in:
After you finish, turn off your truck, replace the brake booster hose, wait the prescribed amount of time, and your done. No fuss, no muss.
I know, its nothing major, but it does make Sea Foaming (or even using the Motorcraft stuff I would imagine) a little easier and faster.