[denisond3]

Sorry to say, the "gas saver' magnets dont do anything. Gasoline is non-magnetic. It wont have any effect on the engine operation in any way.
I cant recall what the 'code' is for an O2 sensor that is bad, but if all that is wrong is an O2 sensor that is over-age, you can continue to drive the car. There are two O2 sensors, one 'upstream' of the catylytic converter, and another one 'downstream' of it. We drove for a couple of months and a couple of thousand miles with the 'downstream' O2 sensor broken & not even connected. Our mileage on the highway dropped from 32 mpg to 28 mpg. When the weather got warmer and drier, I installed a new sensor, along with a new catylytic converter. (Old one was too rusty to save.)