04 Avalanche Flapping / Popping Noise at speed
July 4th, 2014, 8:34 AM
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04 Avalanche Flapping / Popping Noise at speed
OK, Super frustrated. I have a high mileage 04 Av with 180k on it. It is well maintained.
Over the last week, I have had this intermittent flapping / popping noise. It usually happens at around 45 and lasts from 1 - 20 seconds then goes away. There are no vibrations, changes in RPM, and it is not related to turning. There are days when it never happens at all. It almost sounds like a turbo pop off valve going off every second or so, like a pop - pop - pop or flapping sound. The car shifts fine. There is no shudder in the transmission. No clunk when putting it in gear. Does not get worse when turning. It sounds like it is coming from the area under the driver seat.
I ran a scan on it and there are no codes showing. I have an mid level Autel scanner that is usually very good.
The only thing that other thing I see is every once in a while I will get the "Tighten fuel Cap" alarm.
Any and all help would be greatly appreciated.
Over the last week, I have had this intermittent flapping / popping noise. It usually happens at around 45 and lasts from 1 - 20 seconds then goes away. There are no vibrations, changes in RPM, and it is not related to turning. There are days when it never happens at all. It almost sounds like a turbo pop off valve going off every second or so, like a pop - pop - pop or flapping sound. The car shifts fine. There is no shudder in the transmission. No clunk when putting it in gear. Does not get worse when turning. It sounds like it is coming from the area under the driver seat.
I ran a scan on it and there are no codes showing. I have an mid level Autel scanner that is usually very good.
The only thing that other thing I see is every once in a while I will get the "Tighten fuel Cap" alarm.
Any and all help would be greatly appreciated.
July 5th, 2014, 8:49 AM
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OK, Super frustrated. I have a high mileage 04 Av with 180k on it. It is well maintained.
Over the last week, I have had this intermittent flapping / popping noise. It usually happens at around 45 and lasts from 1 - 20 seconds then goes away. There are no vibrations, changes in RPM, and it is not related to turning. There are days when it never happens at all. It almost sounds like a turbo pop off valve going off every second or so, like a pop - pop - pop or flapping sound. The car shifts fine. There is no shudder in the transmission. No clunk when putting it in gear. Does not get worse when turning. It sounds like it is coming from the area under the driver seat.
I ran a scan on it and there are no codes showing. I have an mid level Autel scanner that is usually very good.
The only thing that other thing I see is every once in a while I will get the "Tighten fuel Cap" alarm.
Any and all help would be greatly appreciated.
Over the last week, I have had this intermittent flapping / popping noise. It usually happens at around 45 and lasts from 1 - 20 seconds then goes away. There are no vibrations, changes in RPM, and it is not related to turning. There are days when it never happens at all. It almost sounds like a turbo pop off valve going off every second or so, like a pop - pop - pop or flapping sound. The car shifts fine. There is no shudder in the transmission. No clunk when putting it in gear. Does not get worse when turning. It sounds like it is coming from the area under the driver seat.
I ran a scan on it and there are no codes showing. I have an mid level Autel scanner that is usually very good.
The only thing that other thing I see is every once in a while I will get the "Tighten fuel Cap" alarm.
Any and all help would be greatly appreciated.
I am not sure what to make of it. I initially thought it was something stuck on a half shaft by the sound of it. It seems to increase the frequency of the flapping / popping with an increase in engine speed, but I can not confirm it 100%.
Also, I have a fairly high level Autel reader (MaxiDiag Elite) and there are no codes showing with either DTC reader or reading the individual GM modules. I am fairly certain that a misfire, pressure problem, or improper richness levels would be picked up by the reader.
The sounds seems to be coming from the underside of the vehicle near the driver, but it is difficult to pinpoint, since it does not happen with the vehicle is stationary.
March 28th, 2015, 10:16 PM
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I have had my Avalanche since it was new in 04. Do you have a bug deflector on it? I found that when I had one, it made the wind pop randomly on the windshield. People thought I was off my rocker, but without it there was no noise... and with.. it did. Hope this helps and not to late!!
Digger
Digger
Last edited by Digger4ku; March 28th, 2015 at 10:17 PM. Reason: mispelling
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