I have a 97 caravan 3L. I went to start it today and it turned over a little then made a clunking noise and then there was nothing. I left it for a bit and tried to start it again, it started fine. Went to drive it and the check engine light came on and it started to not run proper. It was kind of sputtering. I turned around to go back and it started smoking. I shut the van off and let it sit for a minute. I tried to start it again and it turned over and made a huge clunking sound as if someone stuck something in the engine and jammed it. Any ideas as to what it could be?