Toyota Repair: check engine light, smog check, toyota corolla

Question
My check engine light is on. I have a 2000 toyota corolla. I have had prices of 65-90 dollars to simply tell me what it indicates. the last time it was activated, i had to replace the catalytic converter. Can i just ignore it? Also, when i drive and accelerate, i hear a rattling like marbles. I have used regular gas. Should i upgrade the gas? I have 124,000 miles. Thanks

Answer
It's too difficult to diagnose a rattle sound you hear since I am not there to hear it. It could very well be pre-ignition, but I don't know. You can try a fuel upgrade or fuel octane additive and see what happens. In regard to a charge for a code diagnosis, you are at the mercy of the repair shop unless you have a scanner of your own. Of course you could ignore the check engine light, but when it comes time for a smog check, you will fail the test if the light is on.