Ford taurus 3 out of 6 misfires?

I have a 2001 ford taurus 24 valve (dual over head cam) (dohc). Cylinders 4,5,6 are misfiring (front 3 cylinders). I've replaced the coil pack, spark plug wires, spark plugs. Cleaned the egr and changed the o2 sensor (what the computer said was bad.) it said it was running rich last time i had it at autozone (2 days ago). I'm now looking at the fuel filter because on this model it has the fuel pressure regulater built into it… I don't know i just need a dorection in which to take action highly upset with this.

148,000 miles.

Then you should quit trying to play mechanic and get someone that knows how to diagnose motor problems. I'll bet you haven't even hooked up a scan tool that can read engine data and sensor voltages yet.