My engine light has been on for some time, however the car has been running fine. Auto Zone completed their free analysis. The HO2 sensors showed up as a possible problem along with the catalytic covertor or large exhaust leak. I changed the sensors and then disconnected the battery to reset the engine light. The car, now, will not idle. It stalls out. I can, however, drive the car around but I have to use my left foot on the brake while I maintain some pressure on the gas pedal at stop signs. Does anyone know what is wrong?