# What is that noise???



## Ninjured (Apr 28, 2006)

Sometimes, when I am sitting at a light, I hear this series of 'pops' coming from the right rear. It is about 5 pops and always sounds the same. I am assuming it is normal but what is it? It sounds almost as though someone is knocking on my window....popPOPpopPOPpop

Also, sometimes (fairly rare) when I am letting out the clutch in first (low speed accel.), the rearend makes a noise and the 'low traction' indicator flashes. I have not been able to duplicate on demand and it has done it since the car was new. It has done it in both first and reverse. I have close to 17k miles now

Cow
2005 CGM m6


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## pab13 (Apr 20, 2006)

i don't know exactly, but if it sound like its inside the rear 1/4 panel the coil springs could be out of it boot and beyond my expetise to fix. Maybe some dealer could help. Im still look for someone decient, even to get an oil change


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## GTOJon (Jan 25, 2005)

WOW...I thought I was crazy. My car has 19,000 miles on it and I've heard that "tap tap tap"......sounds like someone is gently knocking on the rear passenger quarter panel. It used to happen only when I put the car in reverse and I would hear the series of taps/pops just once. Now I occassionally hear them when waiting at a red light. I haven't a clue as to what it is.


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## Holden (Sep 10, 2005)

I've heard that "tap tap tap"......sounds like someone is gently knocking on the rear passenger quarter panel. I hear it when waiting at a red light.
I think it may be somthing to do with gas tank vent system???


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## Justice (Oct 9, 2005)

Ok, you all have this too?!?!

For me, it happens when torque is applied to the drivetrain. Happens more at low speed, and also sometimes during shifts. I had mine in the shop and they determined it was the crossmember bushing that was making the pooping noise. This is the bushing they unbolt and drop to install the upper insulator bushing for the "thunk-in-the-trunk" TSB. 

Let me know if you guys can determine the same.


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## socal gto (Mar 10, 2006)

I think it is a little funny I read this thread before I went to work and when I got out I had the same experience that holden had. I was sitting at a red light and then I heard the tapping from the rear passenger area. I don't know if it matters, but I have an 06 model. What year do you guys have?


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## Justice (Oct 9, 2005)

Mine is an 04


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## GTOJon (Jan 25, 2005)

Mine is an '05.

There was a TSB for a "thud in the trunk"? I heard that once or twice, I just thought it was the body in the trunk.


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## Justice (Oct 9, 2005)

Thunk in the Trunk is when you accelerate "aggressively". As you shift, the crossmember get pushed up and thunks into the body. The TSB installs insulator bushings between the crossmember and the body.


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## ShadesOfGrey (Sep 14, 2005)

That's not true, It's not a launch thing only, cause I get it when I go out and just start the car, a min or two later, knock, knock, knock, and thats before I even put it in gear.

ShadesOfGrey


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## Robertr2000 (Mar 25, 2006)

I was stopped at a light, It was as if some one went "knock, knock, knock" on my right fender or inside the trunk. It's never happened again and I though there was a body in the trunk too...


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## Justice (Oct 9, 2005)

Weird. Mine happens under torque. But it is the passenger rear, and I've already had it narrowed down. I was hoping if others were having issues, there may be a TSB thing for it.


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## Robertr2000 (Mar 25, 2006)

Robertr2000 said:


> "knock, knock, knock" on my right fender or inside the trunk.


Sorry,

My right Rear fender. 



I was thinking maybe the exhaust? Or muffler is knock on something?


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## kaos2be (Apr 28, 2006)

wow , I get the same exact knock and its an 06, how someone finds out what it is


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## I Stall Automatics (Aug 10, 2005)

Do all of you have the stock exhaust system?


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## Holden (Sep 10, 2005)

Holden said:


> I've heard that "tap tap tap"......sounds like someone is gently knocking on the rear passenger quarter panel. I hear it when waiting at a red light.
> I think it may be somthing to do with gas tank vent system???


I think it's a vent solinoide 
If it does it Im stoped @ same light, about 3mi from cold start. First time I realy thought one of the school kids was Knocking on car.


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## Robertr2000 (Mar 25, 2006)

I Stall Automatics said:


> Do all of you have the stock exhaust system?



I do.


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## socal gto (Mar 10, 2006)

Just like robertr2000 I am also still running a stock exhaust.


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## Robertr2000 (Mar 25, 2006)

I have only heard it one time. I thought there was ghost in my back seat :lol:


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## Ninjured (Apr 28, 2006)

I hadn't heard the sound in a while but this morning, on the way to work, sitting at a light, there it was again...

I have stock exhaust...
It is not the drive train or suspension, my best guess is to agree with Holden, that it has something to do with the gas tank venting....


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## greaser32002 (Mar 6, 2006)

I thought I was crazy! I have heard that since I bought the car. It sounds like it comes from the rear right fender well (where the tire is), but I've only heard it when I'm decelerating to a turn. Those little pop,pop, pops, get annoying. I haven't had the stock exhaust since a week after I bought the car. I put flowmasters in right away. I honestly don't know what this could be. Any other Ideas?


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## kaos2be (Apr 28, 2006)

bump


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## ShoddyHog (May 17, 2006)

I had another non-GM car that did the same exact thing...I always assumed it was the fuel pump.


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## btchplz (Mar 12, 2005)

*Something in Common*

This has happened to me too. But if you notice, almost all of us have this problem right before the car gets warmed up. Since it's happened to me in more than one occassion, I've payed attention and I noticed that it makes the Tap Tap Tap noise as soon as my temperature gage starts to move above the first line.

I always warm her up before I start moving and I'm in a tight car port which makes it easier to listen to any sounds the car makes. I never make anything of it because it consistently makes the sound right on cue as soon as that little needle starts to make it's way up the white line.

But I'll see if my dealer knows anything about it. (Doubt it, they can never reproduce any problem I have)


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## TexasAggie (Mar 2, 2005)

btchplz said:


> This has happened to me too. But if you notice, almost all of us have this problem right before the car gets warmed up. Since it's happened to me in more than one occassion, I've payed attention and I noticed that it makes the Tap Tap Tap noise as soon as my temperature gage starts to move above the first line.
> 
> I always warm her up before I start moving and I'm in a tight car port which makes it easier to listen to any sounds the car makes. I never make anything of it because it consistently makes the sound right on cue as soon as that little needle starts to make it's way up the white line.
> 
> But I'll see if my dealer knows anything about it. (Doubt it, they can never reproduce any problem I have)


Sounds like you're the best person to get them to hear it...especially if it does it everytime. My '06 was built last week and should be here end of July. Everytime I read a post like this (odd sounds drive me nuts) I log the page for future review. PLEASE keep us posted.:cheers


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## GTOJon (Jan 25, 2005)

Confirmed.

This sound happens EVERYDAY. As soon as the temp gauge hits 100 (well the first line), sure enough, tap tap tap on the quarter panel.

I have to test...but I believe this only happens on the first start/drive of the car each day. I don't recall hearing it any other time unless the car is completely cooled (such as overnight and into the morning).

Strange, any definitive answers?


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## TheDude (Aug 31, 2006)

ive only experienced the pops once while on a winding road i was in 3rd gear doing 25 to 30mph. came from rear right. 4 quick pops. suspension??


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## Ninjured (Apr 28, 2006)

this has been discussed on other websites and apparently they all do it. 99% sure it is in the fuel system, venting or something. GTOJon is right, it happens when the car is completely cool, some time before it reaches normal operating temperature. I heard other say right when the temp gauge starts to move but I know I've heard when the temp gauge is halfway to normal operating temp.

@theDude- 4-5 quick pops sounds about right but I really only hear it at idle (like sitting at the light at the end of my street) so turn off the radio and listen closely shortly after you start the car in the morning


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## speedwrenchx10 (May 6, 2006)

Like Holden replied earlier it is the Evaporative system checking to see that the fuel system is sealed.The self test is only ran when certain criteria has been met such as fuel level and low engine temp.This noise I have heard at the same stop sign axp 1.5 miles from my home almost every time on the drive to work.If you were to loosen your gas cap your check engine light would come on right after the noise was heard and you should get an evap system code like PO440.If you were to then tighten the cap and it passed the test the next 2 times [poss.the next 2 mornings] the PCM should turn the light back off.


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## speedwrenchx10 (May 6, 2006)

Ninjured said:


> this has been discussed on other websites and apparently they all do it. 99% sure it is in the fuel system, venting or something. GTOJon is right, it happens when the car is completely cool, some time before it reaches normal operating temperature. I heard other say right when the temp gauge starts to move but I know I've heard when the temp gauge is halfway to normal operating temp.
> 
> @theDude- 4-5 quick pops sounds about right but I really only hear it at idle (like sitting at the light at the end of my street) so turn off the radio and listen closely shortly after you start the car in the morning


:agree


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## Justice (Oct 9, 2005)

I know this thread is old, but I did eventually get my popping taken care of. 

My particular problem resulted in a dealer doing the Thunk-in-the-Trunk TSB, and using excessive amounts of loctite on the carrier bolt. Under load, the stress was "popping" the bolt. They took it off, cleaned off the the bolt and re-applied the proper amount of loctite. Problem solved.


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## Deltoid04 (May 27, 2012)

*thud on takeoff*

I also have a slight thud in the rear pass panel. only when I accelerate slowly from a light...4 or 5 thuds hasnt gotten better or worse...04


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## svede1212 (Nov 1, 2005)

The post above you might have the answer. '04s in particular suffered from "thunk in the truck" from the rear subframe bushing and bolt. Slap in some Energy Suspension subframe bushings and new bolts torqued to spec. Another possibility is the slimited slip cones in the rear end worn out or improper lube. Drain and refill rear end with 1.6 qt. Torco 85w140 and 2 ounces of _*Ford*_ type friction modifier.


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