Well, lets see...Ferraris do it, my motorcycle does it, ( birds/bees do it ), my Alfa does it.Date: Wed, 12 May 2004 17:25:05 +1200 From: White Anthony <[email protected]> Subject: [alfa] pop and crackle Out of curiosity, can anyone explain what causes the pop and crackle in the exhaust on deceleration, or off-throttle going down a hill? How would one increase or decrease these sounds? Regards, Anthony White Wellington, NZ