I was driving my car a couple of days ago when the Check Engine light started blinking . My car lost power but didn't stalled. I was near my house so I drove for a few miles instead of calling a tow truck . The next Day , I found it it was a misfire on cylinder 2 and needed the ignition coil replace (CODE P0302 ). I got replaced the ignition coil at my local shop and drove to work. Ten Miles Later , The CEL came back on. The car seems to be driving normally . I took it today to Autozone and They Got a new CODe : P0420 : Catalyst System Efficiency Below Threshold B1. Does this mean I need a new CAT ? or does anyone know any alternative fixes ?