What was your car acting like when your O2's went.

 

O2 sensors can do a heck of alot to your car when they go bad...bad gas mileage, misfires, poor driveability. Since the PCM uses the O2 sensor as the main sensor in closed loop to determine fuel delivery, if the sensor is not reading right, it will be adding the incorrect amount of fuel for the situation and can cause excessive rich/lean conditions which leads to the poor driveability symptoms.

Hope this helps.