Catalytic Converter clogged on 2001 Mazda 626?

I have a 2002 Mazda MPV. The CEL came on in Nov 2008. I took it in for diagnostics without delay and was told it was a non-specific transmission code. I have made sure the gas cap is always on well. Over the last couple months the CEL has gone off for periods of a few days, but it always seems to come back on. The first place I took it said the non-specific problem would not cause me to have a wreck or drop the transmission and to drive it that way. I talked to someone at the Mazda dealer and he also said not to worry (but he was selling me a motorcycle). Now the Mazda dealer in our area has declared Chapter 7 bankruptcy, wiping out the 7 surrounding dealerships I had available. I could look up the code again–it’s in my car. So, does the on and off nature (mostly on) of the CEL mean something?