2006 Ford Taurus • 95,000 miles

I have a 2006 Ford Taurus 3.0 V6. My check engine light came on and I got it scanned at the parts store. The reading was a misfire.(It was not noticable.) Since my car has 95,000 miles on the original plugs and wires I assumed that was the problem. I changed both items and now there is a much larger misfire. I then changed the coil pack as the next step and the misfire just seems to be getting worse. I properly gapped all the plugs and the wires are not crossed and are going to the correct cyclinders.
June 28, 2012.

What is the misfire code? P0300?

Jun 28, 2012.
I didn't get the code. I just saw that is said misfire. I haven't let it run for more than 5 minutes now and the check engine light hasn't returned.

Jun 28, 2012.
Run the car @ idle. Start pulling ignition wires one at a time to see which cylinder is not firing. Start hear

Jun 28, 2012.