Ive had my truck for almost 2 months now. It has 77k on it and yesterday i drove on the highway for a couple hundred miles till I needed fuel. When i stopped white smoke started coming out of my exhaust about 30 seconds after i had stopped. It did not idle rough or run rough at all. The truck is running perfectly. It has not done this before and it seems to only do it if i drive it for a long distance. I drove it to class this morning which is only like 15 miles down the road and when i parked i let it cool down and no white smoke appeared. If anyone could help me out please do!!!