There's like a rattling or weird vibration I hear around 4500 RPM. I was wondering if anyone else had noticed it?

I only have 38000 miles on it.

I also notice that there's not much torque after that RPM - 4500, but I think that's just how the engine is designed.

 

I have a weird noise but its more around 3000 rpm on my 03 sedan. The harder on the throttle the louder it is. It kinda sounds like shhhhhhhhhh or a ssssssssssss ( NOT the the kind of whistle that an intake makes) sound coming from the passenger side. Its only in that rpm range in every gear. Is this also what your hearing?

 

do you have an intake?

 

No, I'm pretty sure everything's stock. It sounds like some sort of rattling. It's not smooth. It almost sounds like the car is resonating.

Everything sounds smooth until 4500, and from there the engine starts sounding very harsh. Also the car starts vibrating like crazy.

 

Definitely not. The VQ really hits its stride after 4000, with peak torque and HP in the mid 5K's. My car really explodes when it gets to 4K, and hits redline easily. If you're losing power around there, then something isn't right.

Have you checked your air filter? What kind of gas are you using? Have someone rev it slowly up to 5500 RPM's or so while you listen to the engine with the hood up. Try to do this while parked, not while in motion . You may hear something out of the ordinary and be able to locate the sound more precisely.

 

I guess I didn't read this part closely enough. You might want to check your motor mounts. You could have a worn bushing. Check the NVH files I attached. Sorry about the picture one, I can't get it to show up correctly.

 

hmm good reference.

 

i was noticing that sound on my 2005 g35 an the throttle was lagging alot, barely any pick up after that. It had been making that sound for about 2 weeks before my engline blew an i threw a rod through the bottom of the block. You should get it checked before something worse could happen. I learned the hard way.

 

obviously there's not going to be much torque after 4500 since torque tops in at 4800 for all the vq35de engines, i do get a a vibration and some type of a weird humming from the exhaust throughout the whole car, this happens when i let off the gas when in high rpms sometimes, it might be the electric dual-mode muffler as infinitihelp.com states my car has, i think it opens a valve electronically at high rpms for more flow and closes it at low rpms for more torque, your problem might be similar to 05'G 's the blown rod thing, check your oil level, a guy i bought a supra off of, blew his rod due to driving with no oil