UDel

I have noticed for a few weeks when I accelerate at low speed it sounds noisier, I would not say it is a really odd or alarming sound, just a little louder rumbling, boat motor, fart can exhaust sound then I normally remember hearing. It does not make the noise when you lift your foot off the gas or just keep it on the gas to go the same pace, just when you ask for more acceleration when going slow. Once it is moving past 40 I don't really hear it. I normally have the radio up pretty loud so it may have been making that noise longer but I just noticed it a few weeks ago when I did not have the radio up. I had noticed a slight lag/weakened acceleration which started worrying me like it was struggling a little even though I did a fresh oil change/air filter change but then I noticed the ECO button was switched on and I switched it to power which helped make it feel normal again.

I originally thought it was the engine and possibly intake/throttle body because it sounds more like it is coming from the engine but then I was thinking it may be the exhaust manifold gasket or something to do with the exhaust too. It is not really loud, no louder then many other cars when acceleratiing but my GS430 engine/exhaust has always been very quiet unless I get on it and the noise is something I have noticed. Any ideas?

Mr Jokster

iTrader: (8)

Could be a pin hole from a rock or something that pierced the exhaust somewhere. This happened to me once, it actually sounded pretty sexy but yea, for me too it was very very low and only at about the same speed. I went under my car and inspected the exhaust tubing and found a small dent from presumably a rock with a tiny pin hole.

Just my 2 cents Still could be anything else though, this is just something to consider.

lexo98

iTrader: (2)

Run your hand around your tires. See if the feel uneven. Is the sound similar to a 4x4

UDel

I was thinking it could be something like that, I will get under my car again and take a look and maybe tighten the bolts where the exhaust manifold is to see if that makes any difference.

UDel

Yeah, it is a little similar to a 4x4 truck but not as loud or as "crude", just not as quiet as the car used to be. I did get new tires a few months ago. My steering wheel has always been canted a little but the car stays straight when you let go of the wheel. What are you thinking, out of balance, it sounds more like it is coming from the engine and maybe exhaust or are you thinking the out of balance can cause the engine to struggle a little more.

Lukas99GS

I've read on many posts changing the engine mounts makes a huge difference on noise on our cars when they get older. Of course that's not a cheap thing to pay for and its not really a repair you need to do, but food for thought.

lexo98

iTrader: (2)

Out of balance too long or bad suspension components can cause the tires to wear irregular. Just a thought. I've had a rumble related to bad tires from worn suspension components before.

Mr Jokster

iTrader: (8)

Well if its a gasket, you'll usually hear more of a ticking than a rumble.

The motor mount is a good idea too, but you'd feel that from the beginning of your acceleration rather than just at 40. As for the tire thing, if it were that, you'd hear it pretty much at any speed.

Is the rumble something you feel too, or just hear? When I say feel, I mean very much feel like mechanical not like exhaust. If its exhaust, you should be able to hear it at idle. Try revving your engine while in park and see if you can hear it at any RPM, this will at least eliminate if its the exhaust.

UDel

Just to update, it has not really gone away, I did not get under my car but jacked it up a little and had my gf rev my car though to see if I could see anything with the exhaust. I did not see anything but did not take a very close look. I was also thinking possibly the engine mounts.

I did notice the sound seemed to get louder and more noticeable under higher rpms yesterday which irritated me because I was now thinking something could be wrong I just can't figure out. The sound is more of a resonance growl, almost sounds like a sporty intake when accelerating which is different from the normal quiet engine, I kind of thought I was feeling a little of that growl in the accelerator pedal.

I knew it was a longshot but I have noticed my plastic engine cover does not seem to fit very well on top of my engine which is where it also sounds like it is coming from, I took the cover off and then re checked all my fluid levels. My coolant was slightly below the full and p>< p indicator(p>< p little below full) so I added some coolant to the p>< p level just to keep everything at the proper levels.

Today I noticed the growl was almost to mostly gone even at low rpm and all other rpms' when I first started driving, not sure why, on my way home I noticed the growl a little at low rpm again but not as bad as it was. I don't know if the engine cover is enhancing the sound so I hear it more, it is the engine cover that was mostly causing the noise, or maybe just this noise comes and goes for some reason. I will leave the engine cover off for a little to see what happens.

Mr Jokster

iTrader: (8)

Still no video or audio clip?

UDel

I will try but I don't think it will even get picked up on the audio or be noticeable with the regular tire roar, if it does get picked on audio it will likely just sound like normal acceleration to most unless you have lived with the car and notice it does not sound like it normally does which is very quiet but I will still give it a shot..

Lutkis

I had a sound coming from the passenger side (left) foot area which sounded like the exhaust had a little leak.
Sometimes it sounded like something was loose and the loose part was resonating.
It only occurred during start up when the car stood still for a day and at a certain (low) speed.

My guess is it was just water or something in the exhaust 'cause it disappeared after a week or something.

UDel

Here is some audio of the noise.

Unfortunately like I predicted the camera picked up and enhanced every other noise aside from the growl/rumble under acceleration so it is hard to discern. I can video the tach to go along with the sound and post a video file but it pretty much always does it at 1500rpm then tends to go away as you accelerate though you can hear it a little under hard acceleration too. I was hearing it pretty regularly but then on the way home today it suddenly barely made any noise and was almost undetectable under acceleration.

Once you lift off the throttle it goes away. I know most people are going to listen to it and say it sounds like normal acceleration but the car never made that resonance/growl/rumble/slight intake-fart can exhaust sound before and was always super quiet and pretty much noiseless unless you really got on it, almost too quiet for V8. It sounds mostly like it is coming from the engine/top of engine/maybe in front of engine but more back of the engine.

(Just an update, I went out driving tonight with the radio off and the noise was basically gone. I was wondering what could possibly be going on that this noise comes and goes based on different days and how am I going to diagnose it. I then noticed I had my AC off, switched it off on the way home, I think I remember turning the AC off before and it not making much difference but when I turned the AC back on the noise came back a bit though not as loud as it was today. At one point I turned the AC on heard the noise, turned it off and the noise went away but at other times it seemed to more or less fade it, not like on and off when using the AC. I am now 70-80% sure this is tied to using the AC. I will check some of the bolts and belt leading the the AC compressor unit to see what is going on, the AC seems to run fine, it is not loud, but I do sometimes here and there have the hamsters in the dash sound likely to do with a servo motor .)

UDel

I was watching motorweek and heard them talking about possible balancer/pulley issues, since the issue seems somewhat tied to turning the AC on but not fully I might look into that, any way of telling if there is a issue with the balancer/pulley for the accessory belts.

karolgt

Hi

Did you resolve the problem? I think I have similar problem, but I have it only every 2-3 months any only when is raining