I noticed just today that my engine seems to be ticking abnormally loud. It always has some ticking noise, but today, it seemed much worse. Also, when revved between 3500, and 5500, it doesn't have quite the same sound as usual. It's not as deep, more whiney. I plan on taking it in to Ford first thing Monday morning, but does anyone have any suggestions or clues as to what could be wrong?