I've read and believe that you co...uld just use a water bottle/spritzer and pick up vac leaks, you'd certainly notice a dip when it gets to the engine. Old school method of decarbonizing engine is what I hear.
I wouldn't put steam into it like that. Can't say why, but it sounds like a bad idea to me...intake doesn't get that hot usually...nor would many sensors and the like...you could use a cigar and just blow it in manually...but water mist should be noticeable. Guys also use carb cleaner and spray it around too...listening for a change in rpms.