Strange sound high gear/low rpms

[Varnell]

I've found multiple threads with the same topic on the internet ranging from subarus to mazdas to acuras. None came to a conclusion, though. Likewise the two related YouTube videos yielded no answers.

To save some trouble, I know you're not supposed to drive in fifth gear while doing 20mph. However, this sound was not present just a few months ago. I had a bad motor mount, so I assumed it was that. I replaced the motor mount today and the sound still occurs. Any gear higher than 2nd will make the sound under 2000rpms. Instances where I'm in 4th gear and I don't feel like downshifting as the car in front of me slows to turn. That usually means I'll drop to 30-40mph and then increase pressure on the gas to accelerate back to the speed limit. This is where I notice the sound naturally. I then spend the next minute or two replicating the scenario to try and pinpoint the noise. I'll post my own video soon.

The best way I can describe the sound is that it comes from the passenger side of the engine and it sounds like a muted yet over exaggerated acceleration.

http://forum.miata.net/vb/showthread.php?t=476023

http://forums.tdiclub.com/showthread.php?t=338797

http://rl.acurazine.com/forums/showthread.php?t=858660

http://m.youtube.com/watch?v=A3dpbxZe9no

This video nails the sound. I really only hear it when I roll my windows up like this driver does about 15 seconds into it.
http://m.youtube.com/watch?v=kZ9qEF2-6b8

 

[Brimstone Brown]

Maybe your throwout bearing. It was hard for me to hear it on my phone but what your describing sounds like an issue I had with my gsr. Never could figure out what it was until it was time to replace the clutch.

 

[Varnell]

My clutch is a year old. I'll look into it, though. Thanks.

I was thinking fuel lines, transmission, or exhaust. Pretty specific, I know. lol

 

[Varnell]

My car has also not been wanting to start up lately. Since then I've replaced the starter and battery. The alternator is reading fine. I'm thinking it fuel pump/lines.

The sound when I'm in lower rpms seems fluid and in correlation to pressing the gas. My first thought was that it sounded like choked fuel. Hopefully this will work.