We also have a '04 Duratec Taurus and I must say that replacing the plugs was not that hard. Just make sure you use motorcraft replacements. Simply go to the motorcraft web site, enter your VIN number, and it will tell you which ones are the correct ones. By the way, that engine does NOT have a PCV valve, so don't bother looking for one. Took me 3 days to learn this, and that was after we tore half the engine apart
