I’ve started running a turn-down in place of a magnaflow muffler. It now seems laggy down low and doesn’t pull as cleanly, but clears out at high rpms. Also for the first time, threw a CEL from a launch. I don’t imagine the 3" muffler was much of a restriction. Could the open exhaust noise effect the knock sensor? I’ve read about and felt my car stumble when lined up too closely behind a loud V8. If this is the case can it be tuned out? Stage 0+, 3" DP, highflow cat, stock fuel pump.

Thanks!