I have a 97 Chev Cav Z24 and the check engine light is on. It is failing e-check because of this. I took it to AutoZone and got and error code P0420. Does anyone know what I need to do to get that check engine light off? The car is running fine. I have to get the car e-checked to get my tags renewed and I am running out of time and I don't really have much money for a repair. All suggestions would be greatly appreciated.