My check engine light will not go off. I had a diagnostic check done and it showed that I need a catalytic converter. However, as I wrote to you before, my key is still stuck in the ignition but the car will start when it is in Park. It seems that for days the car will drive okay, then all of a sudden I'll be driving it & it will cut out and just stop. After letting it rest for about 45 min. it will start again. I just replaced the battery 2 weeks ago. Do you know what could be causing this? Any help is most appreciated!