low-bank 1.What does it mean.? I have already changed the spark plugs as well as the wires.I put fuel injector cleaner in it as well.Is it true that all is left is to change the cat converter?

It would help to know what the code actually was maybe like P0204? Was it Bank 1 Sensor 1, or Bank 1 Sensor 2? I would try changing the O2 sensor that set the code.

It means you will have to replace the catalytic converter,very pricey.Replace the rear oxygen sensor may buy some time before the code return.