[s5uewf]

decel burble and popping is due to a lean condition usually on decel. The gas/air is not ignited in the cylinder and passes into the exhaust header, where it accumulates with discharge from other cylinders and is ignited by the hot headers or by a spark in one of the cylinders.

backfires are usually from rich mixtures. They are different.

CIS generally does not burble and pop because the catalytic converter burns up waste and also muffles a lot of the noise when combined with the muffler. Remove the catalytic converter or swap in headers and you will likley get some popping depending upon how your WUR is adjusted.

If Motronic shuts off fuel on decel, there is no fule to burn in the exhaust, so no popping.