idle stall, rough shift now

2003 CADILLAC CTS
194,000 MILES • 6 CYL • AUTOMATIC
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FLYEYES
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car was normal. stopped at a stop light then car idle was rough and stalled out. Tried to restart and that was difficult, had to give it gas and rev. It wanted to shut off and on screen said engine power reduced and drove slow. I pulled into a parking spot. Turned off. Restarted it and idle was rough for a few seconds then tried to normalize. I drove it a few more miles below thirty five mph. During this drive, car shifted in and out of gear hard. i will try to get codes soon. Any help on this would be greatly appreciated. I have put a lot of maintenance and blood, sweat and tears into trying to keep it on the road. I recently put two new o2 sensors at the bottom of the engine. i know there are two at the top.
Sep 26, 2017 at 6:16 AM
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STRAILER
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It sounds like you have a catalytic converter that is falling apart. This will cause the engine to stall and run bad and cause the transmission problem as well due to the low vacuum. I would follow these guides.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

and

https://www.2carpros.com/articles/stall-at-idle

and you will need to raise the car

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

Please let us know what you find.

Cheers, Ken
Sep 27, 2017 at 12:55 PM