I have a 2012 g37 sedan with 113k miles on it. I recently ran into this strange droning sound right around 2k RPMs while I'm cruising going probably 30-40 mph, so I assume like 5th gear, I have an automatic. It makes the sound only when I'm on the gas, and when I take my foot off the gas it stops. Theirs no sound outside of that RPM range which is weird. This leads me to believe that it's possibly the throttle bodies, I hope that's the case. There would also be an occasional more loud vibration around the same RPM range which sounded almost like it was under my car? it's hard to tell exactly where that sound is coming from, but the more subtle one is coming from what sounds like the engine...i think. it's almost like a low-pitched whistle (hard to describe). I then had an issue with starting my car, which has happened twice now. I start it up it goes to like 1k RPM, then starts to lose RPM and dies. I was able to get it started after like 2-4 attempts, just a little scared after that cause now it could be my injectors. Anyways I could really use some opinion from someone more experienced on what the issue could be, and if you've heard of something like this before, thank you so much!

 

Start off by cleaning out the throttle bodies, and MAF sensor. After cleaning perform a throttle position relearn see if that fixes the issue.

For a drone, I always had a bit of drone in that range with stock exhaust. Also, go under the car and check the y-pipe flex pipes that can get damaged over time which might be your cause for the low pitch whistle.

 

Thanks a lot man, I appreciate it. I got a muffler delete recently too, its just weird that its only in that rpm range when im on the gas. ill be cleaning the throttle bodies soon and let you know what happens!

 

Any news with fixing it ?