I recently (as in yesterday) bought a 97 f250 with 145k. the truck is in pretty good shape and runs great. tonight i was driving home and noticed the white smoke from the tailpipe. not good. so as best as i can tell it loads up on coolant when the engine is in a high vacuum scenario. deceleration and idle. if you are accelerating the smoke clears up and goes away. the coolant that hasnt been burned away is nasty looking and smells strongly of gas. there is no sign of water in the oil as of yet. it also didnt seem like the cooling system was over pressurized. does this seem more like a head gasket or could it be the intake? my knowledge of these engines is lacking in comparison to my GM knowledge. i have owned one before but it was always great and never thought of giving me issues. any help is greatly appreciated

Ryan