Backfire on deceleration?

I have the same problem with my 5.9 factory EFI Magnum. Someone told me it could be the fuel sync, but I can't see how the injectors spraying the intake valve a little too early or too late could cause an issue on the exhaust side.

@vegasanthony have you checked your fuel sync setting? I'm running OBD1 so it's not a simple thing for me. I used my best guess and seat of the pants to tune the sync.

Not likely the fuel sync. I've corrected many of those, back in the day; none of them caused an issue like this. Impossible? Well there's always something that teaches us something new...On that note, how can you not get a hold of a scan tool for OBD-1 ? Chrysler used that same connector from the '80's, up until '95. I suppose, being in Ontario limits your availability, especially, if you're in a remote area. I would think maybe an older repair shop would have something. A lot of aftermarket scan tools had that capability, maybe you can find one, or even better - find an old Chrysler DRB II, or III. They are out there.