Same thing happened to me. Two months ago it had a misfire in cylinder 1, would randomly stutter at startup for a little bit and then it'd be fine, it would misfire really bad on hard acceleration, and eventually it blew. I have an extended warranty so I took it to Ford. They knew about the problem, and had to hash it out with my warranty company. My warranty company, Route 66, refused to pay for a reman long block, and insisted on putting in a used long block. Ford put in the used long block and then I had it all of 30 minutes before that motor blew. Took it back and they had to put in another used motor, per Route 66, and was without it for another month. I just recently got it back about two weeks ago and it's been fine, but I know it's a matter of when, not if it's going to blow.