john smack

take your digital camara and put it under the jeep get in it and rev it, check the video see if that help pin point where the noise is comming from. Keep changing the position of the camara until you hear the sound the loudest

PoorDad

I got under my Jeep yesterday and checked all of the bolts associated with the exhaust. They were all tight. What I am assuming are my catalytic converters (the bulbous part of the exhaust on each side) are both covered with black stuff that does not rub off easily. One of the heat shields was bent in a way that it may have rubbed on something, so I moved it. I did not hear the rattle today, but I was only driving locally. The rattle seems to only show up if I have driven some distance. I will see tomorrow when I drive back to work if the rattle continues.

I would try the video method, but I dont have a camera. I will get a buddy to help when I can.

Does it bark? Dont know what you mean by that, but I have not heard anything when slowing or stopping, just accelerating.

bigdeenus

I had a similar problem - strange rattle everytime I gave her gas - I checked the above-mentioned link in my exhaust, noticed some black soot indicating a leak, tightened her up and no more rattle. I guess that's what I get for not taking her into the shop to install the new exhaust!

PoorDad

still have the accelerator rattle. There is black soot on both of my catalytic converter (or at least what I think is the cat) i take it that is not supposed to be there?

PoorDad

Went to a muffler shop after the dealer said, "I dont hear anything but your aftermarket muffler." The guy there said that JK exhaust pipes are double walled, and that the interior wall will rattle against the outer wall, but it will not hurt anything. They want 70 bucks to make it stop. I think I will just turn up my radio.

TINMAN080

poor dad- check for metal scrap caught up under the JK- if candy apple red with white stripes- its a tricycle....remove scrap, power wash and you are good to go....

mkjeep

Double walled exhaust pipe? New one on me. Muffler maybe, but exhaust pipe?

TINMAN080

[QUOTE=mkjeep;1457502]Double walled exhaust pipe? New one on me. Muffler maybe, but exhaust pipe?[/QUOTE Yes back during the 60's and 70's GM used double walled exhaust pipe, IT DOES NOT AND WILL NOT RATTLE. What it does do really WELL is the inner pipe will heat up and collapse, blocking the exhaust flow from the engine. You can take a 472 cubic inch V/8, floor it and do 25 mph tops. I seriously doubt anyone is using double wall pipe any more, it required all GM exhaust systems to be replaced when the vehicles got 70,000 miles or so....

PoorDad

Just my luck to get a 1970's GM exhaust system on my JK! I guess I will have to go to another muffler place and see what kind of BS they come up with. The guy I talked to said "All the new Jeeps have double walled exhaust."

EmergedRock

I had a weird noise underneath my Jeep too. In the past I've had to replace many catalytic converter with other vehicles and was sure that the cats went bad, the noise sounded like a bat cat. But I only have 12K miles on the Jeep. I took it to a local shop that installed my MBRP muffler, yelling they did something. They took a look and with the engine on and lifted up, and it turns out that it was the skid plate rubbing the exhaust pipe. I remember now a few weeks ago I rubbed a rock 4 bying. They fixed it for free in about 2 minutes. Sweet, best thing ever.