Originally Posted by nvcballr10
hey guys, I just bought a 2001 5.9 and was looking into getting a flowmaster system for it. I was looking at the 40,44 and 50 series. just wondering what might sound better? performance? any input is welcome, its my first truck just want to do the right thing. Let me know thanks all
I had a 50 series flowmaster installed in place of the stock muffler about a year ago. Love the rumble of the engine , but ever since then I have had a lean condition. Tried 180 thermostat, K&N air filter, and superchips flashpaq tuner but still have too lean condition causing pre-ignition pinging.