Noise at idle

[fjcruiserpd]

93' Automatic 3.0 168,000 miles.

I'm having an issue with a sound that I can't track down. I've noticed it happens on two different occasions.

When I come to a stop or when I simply let off the accelerator when on the road/highway.

It sounds like something rattling/vibrating or like something having a hard time closing or opening.

The sound instantly goes away the moment I even slightly engage the accelerator.

I know diagnosing sounds is difficult on a forum but maybe someone else has had experience with this?

Maybe noise at idle isn't the right way to put it but it's the only title I could think of.

 

[541joseph]

93' Automatic 3.0 168,000 miles.

I'm having an issue with a sound that I can't track down. I've noticed it happens on two different occasions.

When I come to a stop or when I simply let off the accelerator when on the road/highway.

It sounds like something rattling/vibrating or like something having a hard time closing or opening.

The sound instantly goes away the moment I even slightly engage the accelerator.

I know diagnosing sounds is difficult on a forum but maybe someone else has had experience with this?

Maybe noise at idle isn't the right way to put it but it's the only title I could think of.

Heat shield on the exhaust. Check all the bolts and I'd take part of it off to see if there are rocks in it

 

[fjcruiserpd]

Heat shield on the exhaust. Check all the bolts and I'd take part of it off to see if there are rocks in it

Hmmm, heat shield. Guess it's time to learn what and where that is.

I'm not a mechanic just an occasional DIY-er.

Thanks for the advice though!

 

[fjcruiserpd]

Noise persists. Now with video! (YouTube)

So I still haven't been able to track down the noise. Mostly due to the fact that I just don't know where to begin and haven't had to the time to investigate.

However, the noise is getting louder – especially in the morning. Regardless of how cold or warm it is outside, when I got to start it for the first time of the day, the noise is there. If I let the car run for maybe a minute or two it will eventually stop. But if I don't let it run and just drive off, the noise gets louder as I begin to accelerate but then disappear the more I press the gas peddle. When I let off the pedal the rattle returns.

This cycle continues until I get on the freeway and then it's gone.

Anyway, here is a video of the sound. I recorded it this morning. It shows the sound and then the end of the sound around the 13 second mark. I tried to point the camera in the direction where the sound seems to be the loudest. See link below for video on YouTube:

https://www.youtube.com/watch?v=FfD9dwKrUSs

 

[541joseph]

Sounds like valve noise and and exhaust leak. What's your oil pressure gage read?

 

[fjcruiserpd]

Sounds like valve noise and and exhaust leak. What's your oil pressure gage read?

Oil pressure gauge is always in the middle. I'm assuming that's normal pressure(?).

 

[fjcruiserpd]

Sounds like valve noise and and exhaust leak. What's your oil pressure gage read?

Any recommendations on how I can further investigate the possibility of a valve issue and exhaust leak?

I'm not a seasoned mechanic but am not afraid of getting there and getting dirty so long as it isn't too difficult.

 

[541joseph]

Any recommendations on how I can further investigate the possibility of a valve issue and exhaust leak?

I'm not a seasoned mechanic but am not afraid of getting there and getting dirty so long as it isn't too difficult.

Next oil change out some thicker oil oem or wix filter and see if it gets better. It's really nothing to worry about my car does it it's just annoying. To fix it you need to have heads rebuilt and make sure that it has good oil pressure with an external gauge. Exhaust leak is probably either manifold or where the manifold and down pipe meat you can see if you can feel it by getting under the car and with it running and see if you can feel where it's coming from with your hand

 

[91'4bee]

In your posted video it sounds like your warming the engine up. Now I have never experienced this but if I was to guess it might have something to do with the Air injection valve or EGR(exhaust gas recirculation valve) that is connected to the passenger side exhaust manifold. The reason I say this is because when the noise stops, it sounds like a normal running motor. The noise itself sounds exhaust related but exhaust leaks don't usually stop like that, so that is why I am leaning towards those emission things connected to the manifold because those valves open and close depending on vacuum and throttle position I think.

Hope this gives some ideas

 

[fjcruiserpd]

In your posted video it sounds like your warming the engine up. Now I have never experienced this but if I was to guess it might have something to do with the Air injection valve or EGR(exhaust gas recirculation valve) that is connected to the passenger side exhaust manifold. The reason I say this is because when the noise stops, it sounds like a normal running motor. The noise itself sounds exhaust related but exhaust leaks don't usually stop like that, so that is why I am leaning towards those emission things connected to the manifold because those valves open and close depending on vacuum and throttle position I think.

Hope this gives some ideas

Thanks for this insight. I will look into the EGR and Air Injection Valve.