Loud intermittant electronic noise new FX35

[amadorrs]

I have searched all posts and archives and have not found this. My car is a new FX35, RWD, with nav system and I'll be taking it in this week since this has been going on for days now. When driving idle or not, ac on or off, radio on or off, it makes a noise that sounds like the high pitch sound of a tv channel going off the air. It starts low and increases in decibels to the point that you want to stop driving. It sometimes goes away for a week and then returns, sometimes when it's cold, sometimes only after driving awhile. It has stopped twice as I've approached the Infiniti dealer but i finally got a mechanic to hear it at the end of the day since i knew they would think I was crazy. Any ideas?

[jtesensky]

Is your tire pressure light on in your dash?

[amadorrs]

No tire pressure lights or any warning lights show up on dash (except normal seat belt, etc.). But maybe I should test the tire pressure since the ride is bumpier than the car I test drove.

[maxnix]

But maybe I should test the tire pressure since the ride is bumpier than the car I test drove.

Do you have a Sport model while the demonstrator may have not been?

[amadorrs]

Not the sports model according to the sticker. I'm aware that's supposed to be a bumpier ride.