On sunday I bought a 1996 dodge intrepid, the guy I bought it from said it needed a catalytic converter, but it ran (I only paid $600 for it). I have checked around and there is 3 catalytic converters on this car, I am not sure which one is out. The check engine light was on so I took it to Auto Zone and they put it on the machine and said it was the 02 sensor( driver side down stream). So my question is, could it just be the sensor or do I need to pay someone to check the catalytic converter. The catalytic converters are expensive, problems include: no get up(power), jerking( like not getting enough of something), and a hissing( like the car is blowing air). so does anyone know what it could be? catalytic converter or sensor? If the catalytic converter is clogged can I just take it off and clean it? How would I go about doing that? I talked to the dodge place and they confirmed that those catalytic converters are bolted and not welded in, I thought about buying the tech manual and seeing if I could figure out how to get it off....I am not a mechanic, and I am not sure how these things work