Hissing while idling... EVAP system leak?

Sometimes [I would say rarely] when I start my ex via the remote start option on the key fob, I hear a hissing sound. It sounds like a tea pot kind of.... It goes away after about a minute. I heard somewhere that it could be a leak in the EVAP system? I also read that this type of leak should trigger a check engine light to turn on? I'm going to bring it up to my dealer during my next service but I just want to know if anyone else is experiencing the same thing. It doesn't really seem to effect the performance of my ex at all. The sound is just odd.

Not a leak but it may be the EVAP system doing a "leak down" test. at Start up the EVAP system has a small compressor that pressurizes the system. it looks for any leak down in the system. It measures the amount of leakage over a 1 minute period. a certain amount is allowed but if it is more than the predetermined limit it will flag the system for a leak. This was a problem when the OBD III rules came out. Especially if you left the gas cap loose or off. You are hearing that compressor running and or hearing the pressurized air venting after the test.

Mine is still doing this on a cold startup. Tea kettling whistle. I had the fuel pump changed and that wasn't it. Is this noise on all of them?