My 03.5 g35 sedan has developed an annoying resonating sound around 45mph. It is loudest under load in top gear. I've had the dealership check it out and they can't find anything wrong. I suppose I should be glad about that eh? She has about 84k on her and it takes away from the sweet sound she used to make . I've searched through threads and haven't seen anything that exactly matches the issue. Thought I would post to see if anyone else has experienced a similar issue/sound.

 

where is the sound coming from? front of car, rear, mid. exhaust area? under the hood?

more information please.

 

I have the same sound, kind of sounds like it's coming from the back of the vehicle. I'm going to try doing a differential fluid change. Doubt that's it but it will make me feel better. I know exactly what you mean by resonating. No idea what it is though.

 

loose exhaust?

 

wheel bearing(s)? - If you turn to the left or right like getting off the freeway, is the noise worse?

Or is the flex piping for the exhaust frayed?

 

The sound appears to be coming from the rear of the car. The dealership has checked out the exhaust system and states that all is fine with no leaks. I wonder if it could be the muffler itself. Doesn't it have a flap that opens up at higher rpms allowing exhaust out both pipes.

 

Does the sound increase or decrease with speed?

How are your rear tires? They getting worn?

If you are at speed and shift trans to N, does it stop?

I'm thinking wheel bearings or tires

 

I had a resonating sound but that was because I was running on like negative tread on my tires lol. The tires were so bad it was about to be smooth, everytime i ran at high speed, I would hear it. Check your tires

 

What RPM is this happening with? My car makes the sound at 1300RPM and worse at 2600RPM. I have an 03.5AT Sedan. Dealer told me all they could hear was some rattling from a cat and gave an estimate for over $1100 to fix. Obviously not worth that price given the problem and I have my doubts that is the issue.

It sure does sound like a muffler, but it only happens at those RPM ranges. If I give it more gas, the sound stops. It only occurs under load, if I put it up on stands and rev to those RPMs it does not occur.

Let us know if you find anything out.

 

I had a really loud sound from the rear of my car only at certain RPM's though.. I mean, it was REALLY loud... I thought my muffler had come loose... then I kicked the snow and ice nuggets off from behind the wheel (you know, the build up from driving around in the winter) and it completely disappeared. I have no clue why, nor do I care, just as long as it wasn't serious.

If its snowing where you're at... Its worth a try?

 

maybe its a sign to go aftermarket!

 

I just bought my car used for the steal of the century with some bald tires but I don't know if that's it. Hopefully it is. Just sounds like it's coming for the rear and becomes a progressively louder whirl after 35 mph. We'll see what happens when I get new rims and tires soon. Bearings sounds right though, we'll see, i'll update.

 

I've replaced the tires just recently and the sound hasn't changed. It definitely sounds engine noise related as it is worse at about 1500rpm to 1800rpm under load. As Jim described, just sitting there revving the engine does not produce the noise.