Good morning all! I hate to make a post like this my first post on the forum but I'm concerned about my 5.0. First off the car is a 2014 5.0 that has been tuned by bama since about 3k miles (currently at 61k). The only mods I have are a JLT cold air and axle back exhaust. The car ran very smoothly and I was an idiot for messing with it but i decided to try a new tune from a different tuner. Once I updated my sct x3 and attempted to load the new tune onto the car, the download failed midway leaving my car uncrankable. I had no choice but to return the car to stock and reached out to my new tuner and he sent me a new file within the hour. This one failed as well. I didn't want to brick my ecu as this car is my daily driver so I returned it to stock and left it as is for the night. The next morning I had to make a quick run to the store but when I cranked the car up, it idled very aggressively. The engine began to knock/pop very loudly to the point of I thought it might blow up in my driveway. I read the car had to relearn how to idle but after looking on YouTube I haven't been able to find another car idle like this. I've heard ghost cam tune but this was much more aggressive, to the point of I really thought this was it. The car drive poorly with the stock tune, idling at around 400-500 rpm and shifting very lazy (A6). When I got home I put the bama tune back on my car and thought all was well but after about 200 or so miles, the cel popped on. I read the code with my sct x3 and it read as a p0420. I researched online this could be as simple as a o2 sensor or as complex as a cat. My question is what are the chances that I did any long term damage to my engine. With the bama tune it runs and idles just as I remember. And as far as the code, is it safe to drive with the cel on? I cant tell any difference. And lastly, is there a way to pinpoint if it's the cats, o2 sensor, or another issue? I