check light on and code shows catalytic converter but car displays none of the symptoms associated with that. what else could it be?
The full description should be catalytic converter efficiency below threshold. The effectiveness of the converter to clean the exhaust gasses would be difficult to measure at home without professional equipment.
This is different from an exhaust restriction which might not cause a system fault.
So you have a P0420?
That indicates a bad cat. Sometimes reality bites and no amount of disbelief can change it.
First, you need to confirm that the code is P0420 or P0430 code and no other codes exist. Do not accept someone else, i.e. auto parts store employee telling you that its the cat and not giving you the code.
The above codes tell you that one of the cats is not working, but that does not always mean that the cat is bad. Anything that upsets the balance of O2 to HC in the exhaust will keep the cat from working properly. A common cause of the cat not working is a leak in the exhaust system between the head and the rear O2 sensor or the rear O2 sensor not working properly.