Sounds are one of the most difficult things to diagnose over the forums. One person's chirp could be another's squeak. So, we need lots of descriptors to help zero in on a locations.
For starters, what model year and engine does your Taurus have? Does the tick seem to change with vehicle speed or engine speed? Did you try shifting in to neutral and playing with the engine speed a bit to see if it changed? Does the tick sound like the noise a water pump or idler pulley may make as the bearing wears (almost like a pinging/rattling noise)?
If you determine that it seems to be in the engine you might consider having a Used Oil Analysis (UOA) performed to determine what materials are out of family for used oil. You could also drain and cut open the oil filter to see if it's trapping a lot of metallic particles.
-Rod