Backfire sound from underneath
So my car works fine. But when I downshifting, even I didn't drive it hard, there are some backfire shot gun cracking sound coming from underneath my car. I do not know what happened and it's very loud. But sometimes it doesn't have any sound. What should I do?
exhaust mod: BBK off road x pipe, borla atak catback and a Airaid intake, 93 steeda race tune.