Sound coming from new Exhaust

[StevenF]

Dear Pagoda Family,

I noticed that a few times, here and there, after I press the gas pedal and then take my foot off to slow down, I hear a "farting/puff " sound --nothing very loud and no backfire.  I was told that it is is some fuel left that is burning off...is that true?

Again, it only happens here and there....

Steven