It may help all to know that the part that was ordered is called a "THROTTLE GASKET."

The mechanic diagnosed it immediately and I received a call back from the dealership service center letting me know that the part would be ordered and ready to be installed sometime next week.

I will report back with an update as soon as the repair has been completed.

Hope this helps all of you searching for answers.

From speaking with the service advisor, the mechanic also did NOT think it was normal and apparently thought the current gasket was faulty.

MR

The gasket is not faulty. They have to replace it when unbolt/adjust the TB (raising it up while tightening it again). Service Bulletin NTB08104 describes it well for them. I just had it done on my Murano - worked - it's incredible driving without that noise!

My '09 Murano is getting the throttle gasket replaced/adjusted this week.
How long did the repair take for you?

The TSB process/gasket replacement takes all of about 30 minutes.

Good luck - cheers

This issue has CONSUMED me ever since I took home my 2009 LE back in May 2008. I have taken it to the dealers twice with the TSB info to fix it.

First time after the fix, the noise (on a scale of 1 to 10), went from a 10 down to a 4. This was WAY better than before where it was almost unbearable hearing that high-pitched dog whistle.

About 6 months later...I took it back because the whistle, although much improved was still there. They did the TSB fix by adjusting the throttle body and replacing the gasket (don't think they replaced the gasket the first time). This time, the whistle went down from a 4 to a 1 or 2. I may be a freak, but if it is real quiet and I get the RPM band in exactly the right spot with just the right amount of gas applied, I still hear it. It is much more faint and I'm probably only one out of 20 people that could hear it (because I've tuned my ear into to), but it is definitely still there.

I am ok with it where it is...but the fact of the matter is that something in the engineering design of the TB is flawed and Nissan let this slide through the cracks. I suppose if I pushed hard enough, I could get a whole new TB installed, but I don't think its worth the fight at this point considering all I had to go through just to convince them to do the TSB fix twice.