BOV Sounds like its sputtering. Problem???

[Merkdizzy]

When i begin to boost, then let off, my apexi twin chambered BOV sounds like it's sputerring. The swhoosh sound, that is. Instead of a smooth swoooosh, it's like swoo-hoo-woo-hoo-sh! Does anyone get what I'm trying to describe? It didn't do this before. Is it normal?

 

[timmy]

My buddy has a greddy tyoe s on his civic, and it sputters.