I was waiting at a traffic light about half way home on my 75 mile commute when the sound of a fart can mufflered car snuck up out of nowhere. There weren't any small cars around me. Where was that sound coming from? Oh, its me!

I took it easy on the gas pedal as anything above feathering it brought forth very large blatting sounds that caused all creatures large and small to scatter. Once home I found that the downpipe had broken clean off at the flange to the exhaust manifold.

What surprised me was all the backfiring that occured when decellerating with the clutch engaged. No backfiring was ever noticed before the exhaust pipe broke. Is it likely that the car was backfiring before but the noise was subdued by the muffler, or does having an open exhaust encourage backfiring?

Thanks,

Joe M