Originally Posted by carta79
You're correct about gas cap reference, but why do you think it's unlikely that the cat has become fouled.
I think that's the problem the cat converter isn't operating.
The one time that I threw a code 67 CEL, the harness plug on the O2 sensor had wiggled loose.... I did a continuity test on both ends of the harness, reconnected the sensor to the subharness, and haven't had a single problem, or symptom indicative of sensor failure since.
In the interest of being pragmatic, I think it's just good to check that the problem isn't electrical..