I hear kind of a "crickets chirping" noise on my 2001 2.7 box when the engine is under full deceleration and the rpm are high enough to cut combustion. Didn't really know it may be a problem - (maybe I'll need to add checking the torque on the spark plugs to my to-do list to rule out that possibility.)
The car is still fairly new to me, and there are other more annoying sounds that I'm trying to diagnose - in particular something that sounds like a rattling heat shield, which only happens in certain RPM areas when the engine is warmed up. There are also some "ticking" sounds which I believe are small exhaust leaks. (Some I've verified are at the clamp joints by the muffler.). Then of course the aftermarket muffler is causing some pretty loud drone. Despite all those noises, it does still sounds awesome when you get the RPMs up! Another coping technique is to turn up the stereo, which sounds great.
