Popping Back down CAI???

[S3 AEX]

Rite not sure about this but just had timing belt and tensioners done on my S3, now when it's idling an I rev it an let the revs drop to normal I get what's sounds like a single pop coming back down the CAI? Abit like an echo down a drain pipe? Sorry for the crap explanation!! Any one had this or know what it could be, all the timing is set up correctly. My engine man light did come on after belt fitting, so scanned it an it came back with camshaft sensor. Cleared the fault drove car and it drives perfect boosts as should an no faults come back up?!

 

[Marshy]

Normal mate
My S3 has always done this through the intake.
I fitted the timing belt and know the timings 100%
Just normal

 

[S3 AEX]

Cheers marshy, set my mind at ease mate.

 

[Marshy]

I only ever notice it when putting it in the garage.
As you say its only as it comes back to idle.

 

[S3 AEX]

Yes that's the one, I've prob only just noticed it as I've always got the radio on but didn't have it on this time.