My car backfires 100% of the time when it is warmed up and goes to 1800 - 4k rpm. It only backfires when I drive my auto on semi and leave it in gear or when I'm parking and give it gas or on neutral. My exhaust has a huge burnt exhaust leak and it sounds nasty, I'm soon going to take the muffler out and leave a y pipe there. Could the exhaust leak be the issue? The car runes smooth as silk. Just a loud squeaking noise when I go through bumps on the left rear side