What to do with seniors after I take off the catalytic converter
If you remove the oxygen sensors from your vehicle, you will ruin the efficiency of the engine, thus consuming around 10 to 20 percent more gas than otherwise required, and also cause early failure of many components such as the spark plugs. The entire engine management system in your car is designed around the data inputs from the oxygen sensors; consequently, removing them will make it impossible for the engine to function optimally as designed. And, of course, if you are in a jurisdiction where annual emission inspections are mandatory, you will fail inspection without the catalytic converter and the O2 sensors.
All components of an emission control system in the U.S. are mandatory and tampering with such equipment could be illegal. We want to help you to get your car into perfect running condition, so I recommend having a certified mechanic, such as one from YourMechanic, come to your location to help you replace the catalytic converters and oxygen sensors if needed.