I took the last section of my exhaust off which included my muffler and added a 3 foot section of 2.5 inch strait pipe. It has a louder deeper sound for sure. Just wanted to see what it would sound like. I can change it back easily...which I may I'm not sure. In regards to what you said it has only back fired once or twice when red lineing first gear. As I said for sure it definitely misfires sometimes mostly when it's warm. So do you think I should just start changing out engine sensors?