Hey guys my truck has only 1600 miles on it and within the last 300-400 miles with the exhaust brake on it makes very loud pop almost as if a backfire only when i press the accel a little after slowing down with the exhaust brake and it does it every time at around 40-50 mph. So for instance im slowing down from 50-45 my foot off of the accel and brake pedal letting the exhaust brake do its thing and make the cool whistle then i go to accelerate a little and it pops almost like a valve is closing hard or even a exhaust backfire??any ideas or is this normal?? Thanks