1.8 L-Jet, new vacuum hoses. The car runs pretty well but pops a lot on decel. It will pop when just spinning down, and makes a LOT of noise when engine braking. I had leaks at the exhaust gaskets at the Monza mufflers, but I fixed those with no improvement. I don't see evidence of leaks anywhere else in the exhaust.

This isn't backfiring, just annoying pops and blats.

Before I start digging deeper into the exhaust, are there other things that could cause this?

try to get more air in the system at idle (higher idle setting). it may help or at least help you to figure it out.

spark plug gaping could help also (cant explain that but noticed this worsen or improve for me while i was testing gaps one day)



Gary

Check for exhaust leaks first.

Remove the copper gaskets from the heads, and inspect for carbon tracks. You should have a clean copper oval section on each gasket.
(copper gasket on head for exhaust, not the copper head gasket)

100%

I agree with the exhaust leaks.