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Discussion Starter #1
I've got an 07 Commander with 4.7 V8. I put a K&N intake in a couple of years ago and it works great. I just put a Gibson cat-back exhaust system and seem to be having an issue. I get an intermittent vibration sound when at warm idle in drive and various other times. Gibson says it's the air intake bringing in too much air and I'm getting blow by. It's pretty annoying. I don't get any codes or lights on the dash. Everything is securely mounted. K&N says its not uncommon and I'll probably just have to live with it. Installer thinks it's a faulty exhaust.
Wondering if anyone else has had this problem and if there's a fix.
Thanks for any help,
Todd
 

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Discussion Starter #3
They're as solid as they can be. The mount is good.
It's a vibration sound but has to be coming from inside the muffler. Not sure about the blow by theory or loose internals inside system.
 

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They're as solid as they can be. The mount is good.
It's a vibration sound but has to be coming from inside the muffler. Not sure about the blow by theory or loose internals inside system.
This:
Gibson says it's the air intake bringing in too much air and I'm getting blow by.
is complete bull****. :icon_confused: I would be upset if someone tried to tell me that.


Have you looked for loose heatshields? Is the catback bolt on or weld on? Otherwise the problem is the muffler. Ask for a replacement.
 

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Discussion Starter #5
Fixed. It was the last bend of the pipe rubbing the frame when it got warm. My buddy, the installer, was able to heat it up and get it off the frame.
He also said the Gibson info about too much air is BS. They really need to watch what they tell people.
Anyway, thanks for the help.
 

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I've got an 07 Commander with 4.7 V8. I put a K&N intake in a couple of years ago and it works great. I just put a Gibson cat-back exhaust system and seem to be having an issue. I get an intermittent vibration sound when at warm idle in drive and various other times. Gibson says it's the air intake bringing in too much air and I'm getting blow by.
That's the most ridiculous explanation I've heard in a LONG time.

That tells me to stay the hell away from Gibson.

I think I am going this route sometime in the next few months;

http://www.carid.com/2008-jeep-commander-exhaust-systems/afe-mach-force-xp-exhaust-systems-45737490.html
 

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Aftermarket intakes can improve air flow into the motor a lot, because the OEM intake system is designed to baffle and reduce intake noise. So the downside of an aftermarket intake is possibly increased induction noise. BUT, I'd imagine that would show up right away and NOT years down the road, as well, I've never heard induction noise that sounded like a vibration.

The exhaust may be banging up against something as it vibrates. Look again, for clearance all around the exhaust parts, as well as the heat shields around the exhaust.
 

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I've got a 1968 dart GT with a 340 4v ThermoQuad and when you stand on it it will sound like a freight train coming through your house or your head down by a large Hoover , but no strange noise from the Commander 5.7

Swanny
 
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