I HAVE A 2003 PONTIAC BONNEVILLE WHAT IS WRONG WITH IT WHEN IT DO A LOT CUTTING BACK AND POPPING NOISE?

Here is a link to a diagnostic walk through for vehicles with a misfire problem or backfire.

It will walk you through the process and is deatiled as well as giving you possible solutions.

Here is the link;

https://www.2carpros.com/articles/engine-misfires-or-runs-rough