I know this is the wrong area but it is the only place i can post right now. I habe 2 RX8s that both start and run for a short time and then shut off. With my OBD programs it is showing my catalytic converter temperature reading suddenly jumps to sometime 9000 degrees about the time it shuts off. Does anyone know what could be causing the computer to think this?

 

First two things that jump out at me are a bad O2 sensor or bad wiring.

 

Two questions......would it be both o2 sensors most likely or just the front or vack? I pulled the front from one of the cars and it appeared to he drippijg oil and fuel. Dies anyone kniw which front o2 sensor is best and reliable? As far as wiring i have tested it all amd it appears good. Coukd it he the ecu.

 

It's not a matter of which is more reliable since they're different sensors. Front is wideband and mounted in the exhaust manifold, rear is narrowband and mounted in the catalyst. They serve different purposes (one for AFR and the other for emissions).

Neither should be wet with anything.

 

It's not the ECU, those failures are extremely rare. Let's ignore the 9000 degrees also, it's clearly wrong and doesn't help us fix anything.

You said it's coated in fuel and oil, so what are the fuel trims via OBD? When did the car last run well? Has the ignition been replaced recently?

You can try replacing the sensor, but I'm not convinced it's broken, yet. The cat temperature is fed by the 2nd O2, if you do choose to start replacing things. But you don't need to do that.