Probably the gas swishing around in the tank would be my guess.I sometimes notice that on occassion with mine. But hard to tell from what you said. Be a little more specific of where its coming from, and we can troubleshoot.
<hr width=60% noshade size=1 align=left><img src="http://publish.hometown.aol.com/jrh382/myhomepage/elantraborbets1.jpg?mtbrand=AOL_US" border=0>
2000 Hyundai Elantra GLS (Photochop)
-PIAA 1100 series driving lights
-PIAA Plasma Headlights
-10" Pioneer sub powered by Kenwood 600 watt amp
The sound is definitely not from the radio. It's hard to pinpoint where exactly it's coming from, but from the driver's seat, it sounds like it's more towards the front where the engine is, in the center. The best way I can describe the sound is that it sounds like air being deflated from a basketball, air mattress, etc.
If you hear this only when you turn off the engine, it's the vacuum system behind your dash equalizing. Your HVAC system uses vacuum pressure to open and close "flapper" valves to control airflow. When you turn off your car, the engine no longer makes vacuum so air rushes into the vacuum system. It makes a "whoosh"ing sound. This is normal.
<hr width=60% noshade size=1 align=left>Later,
Events Coordinator, Las Vegas F-body Assoc.
'96 Elantra GLS
"The shortest distance between two points is a straight line........but, it's not as much fun."
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