No warranty I assume, did you bring it back to the dealer you bought it from? Do they maybe have a short warranty that might cover you? It could be the sign of a bad problem, oil starvation but then again, it could be nothing. Whatever you do, dont just hand the keys over and tell them Ford to have at it, as your bill will be in the multi-thousand dollar range. I would say to take it for another opinion, but if it was oil starvation problem or related, then driving it will mean the death of the motor. Maybe someone else could give you more diagnostic info than I can. Good luck... -Nick