hi there,
i think you'll find the pervious code p0030 is covered by a ford TSB, which involved updating the PCM software in conjunction with changing the hego (lambda). We often find people who have changed them but the light comes back on, so im afraid the only way is to go to a ford dealer who can do the update for you
not what you want to hear i know. you shouldn't need to change the hego again though.