I'm a Chrysler Tech. You will need to replace the upstream o2 sensor. Very common problem. I speak a little Ford and it is related to your HEGO. The problem is the O2 heater sensor. It is open circuit in the sensor. Replace it and that'll fix it. Right off the top of my head I'm not sure but I think there is a flash for that also.... but I'm not 100 percent sure. If mileage is under 80k then the dealer should do it for free under emissions warranty.
