Here's the original thread. Sounded to me like an air flow issue when it warms up.

Maybe someone who understands the resonance flaps better than I can assist.

http://www.peachparts.com/shopforum/showthread.php?t=178073

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)