PCM reset:
Pull negative battery terminal. Wait a minute. Replace. Reset radio and clock.
-OR-
Look in owner's manual under fuses. You can pull the two in the fusebox in the engine bay for the PCM (one is RAM and one is power). I forget the numbers off hand. No need to reset clock and radio with this method.
As already stated, the two first things to do would be to change your fuel filter (every 30k miles, most people forget about doing this, $15 and about 30 minutes time DIY) and the upstream O2 sensor for bank 1 (side closest to driver/firewall and closest to engine and a real PIA to get to on Duratech, closest one to engine on Zetec, about $60 for sensor).
