Issues in 85 ford LTD crown vic

Been doing some maintenance on my car and was wondering about some noises I’m hearing. It only occurs when I coast and the engine brakes itself, but it is a sound similar to a boat or jetski at low speed in the water, a ”blub-BLUB" sound coming through my exhaust ( I only notice it due to a break in my exhaust that occurs under my seat, the replacement is on the way for that). It happens at an irregular rhythm.

Is there a probable cause for this?

It’s called exhaust burble and usually occurs on the overrun. All cars do it, you’re only hearing it due to the broken exhaust.

Yes there is, the broken exhaust pipe.