I changed the plugs in my 3VZE yesterday and after I got everything done when I cranked up the truck it started blowing out a pretty good bit of white smoke and you could see water dripping from the tail pipe. It did it for about 20-30 seconds then stopped. It only did this once. I let it cool down and cranked it again and nothing came out. Even this morning when I cranked it there was no smoke. So I am just trying to figure out what happened and why it only did it once.

 

It sounds like you probably had some oil, or other liquid that built up around the spark plug hole, then it drained into the cylinder when you pulled the spark plugs. I have had this happen, usually on DOHC engines where the spark plug is down a long tube and the valve cover gasket leaks. It can be difficult to completely clean up all the oil before removing the spark plugs on those engines. It is not good to get anything in the cylinder, but as long as it is just oil or something that easily burns off then your engine should be fine. A byproduct of combustion is water, so water drips from the tailpipe if the exhaust is not hot enough to keep the water vaporized. I would not be concerned unless this happens again when you have not removed the spark plugs.