My engine sounds busy (buzzing) at highway speeds at rpms 3000 and above. It stops when I let it out of gear or let off the gas. The noise level is proportional with rpm. Haven't really notice this until I went on a stretch of newly paved highway. Not sure if it is from the engine or exhaust though but for sure it is coming from the front. I realize that the engine makes noise, but I don't ever recall it being this loud or noticeable unless I'm accelerating. BTW, my engine and exhaust is bone stock. Do any of you hear this also?

 

Do you have an Auto or a Manual? If it's a manual maybe the throw out bearing?

 

It's a manual.

 

I actually notice a strange resonance-type buzzy metallic vibration around 3000-4000rpm on acceleration, it's strange. Above 4k though it goes away.

Same thing?

 

No, but I know what you are talking about. I would check the flexible section of the y pipe. One of the y pipe's end ring is probably loose. Happened to mine.

 

The noise is probably your transmission, not your engine.