usually the "popping" noise produced by any car after letting off the accelerator is created by small amounts of unburned fuel being dumped into the exhaust headers and burned off within the exhaust system of the car. This results in the "popping" noise or "back-fire" that you're hearing... This can be louder or softer, or none existent on different cars depending on the muffler used etc...
Don't know why a bump in the rear would have stopped that though... |