I've had my P85 for a few months (End of Sept 2014). About 3 weeks ago I heard a short duration (about 1 second) or so hissing noise. It sounds very similar to air brakes of a truck. I thought that is what is was so I ignored it. But just a couple days ago it happened again and there was no truck in site and it sounded like it was coming from the front of my car on the passenger side. It has been cold here for a couple weeks (Michigan). The air suspension is not changing any position. I know what that sounds like. It happened today about 3 times from the office to home (10 miles). One time I was slowing down and another I was at a steady speed of about 40 mph. Everything feels fine, no concern with ride or steering. I searched for hiss on this site but did not come up with much of anything. Just wondered if anyone else has heard this sound.