I've done this countless times. Not entirely sure how effective it is at cleaning the kind of baked-on gnar in older, neglected Pajeros, but I still like to do it every couple of years. The general rules, as I see them...

1/3 can into a warm engine via vac line, remainder of can in the gas tank.

1. Get the engine up to operating temp.
2. Disconnect a good vac line that runs directly to the intake mani. Dip this into the Seafoam - gently! The engine will bog.
3. Manually open the throttle with your free hand to keep the engine from stalling.
4. When you're almost done, just let the engine suck it down and flood out.
5. Let the engine sit for a couple minutes so the Seafoam can soak in and do it's thang.
6. Pour the remainder of the can into the gas tank.
7. Make sure none of your prissy neighbors (or the police) are outside.
8. Start the vehicle. Might require a little right foot. Let it idle.
9. Admire the epic smoke screen. (We all know this can't be good for the environment.)
10. Butt dyno test.