[shorod]

Which engine does your Taurus have (ie: 12V vulcan, 24V DOHC Duratech, or 32V DOHC SHO)?

A faulty coolant temperature sensor or intake air temperature sensor on any of the engine types could contribute, as could a dirty MAF or pocket of air in the cooling system.

Also, a stuck or partially open EGR valve or faulty DPFE sensor could cause similar symptoms as well.

If you have the Duratech and the secondary intake runner valves are stuck open for some reason, it would definitely cause what you describe.

-Rod