ok i have a 1996 eclipse gs which is completely stock and for about the last year my check engine light has been coming on, when i did the key dance i got code 72, and when i went to autozone they gave me code P0420 and the description "the pch has determined that the catalyst system efficiency for bank 1 is below threshold for the current operating conditions." I had them turn it off several times and i found that if i buy premium gas the light wouldn't come back on as soon, but now it only stays off for a couple days. My guess is that the catalytic converter needs replaced but im really not sure. Also I don't know if this is related or not but recently every so often when i try to start the car it cranks but doesn't start right up i have to hit the gas to make it start; or it starts then shuts right back off. Any suggestions would be greatly appreciated
Thanks,
~Shawn

well 'bank one' usually referes to your front o2 sensor.

If you cat was goin on your car would smell like shit

it did have that rotton egg smell last spring, but I havent noticed it since then