I am a 17 year old kid, that recently purchased a 2010 Dodge Charger Pursuit, with the 5.7l hemi. Like all kids do I cut the mufflers off, a few months after. Then, a month goes by and the car starts to stutter (break up) when I give it around 50 to 70% throttle. I first assumed it was the gas that I was giving it so I switched to a higher octane. That didn’t work, so then I assumed it was the back pressure caused by my mistake, of cutting the exhaust off. So I gave the car to a muffler shop, they cut of the resonator, and added a performance muffler and piped it out back. I got the car back and it is still having the same problem, of breaking up. Anyone have any ideas??