Sheldon

Soo I got the dealer run a diagnosis on my jeep they said the catylic convertor probably went out I replaced the spark plugs and wires bit the engine light isn't on any more but when I go to start the jeep all the lights come on like usallyou but the check engine light stays on and flashes then turns off ? Does that mean I still need to replace the cats only has 70 thousand mIles but I have had replace the fuel injectior and egr valves