I know i probobly spelled ratteling wron, but anyways. I would be driving down the road like and other driver would and i would hear a rattle comming from the front underneith. I know its not the CAT because my friend and I just replaced it a week ago. The ratteling sounds like a bad CAT, but its not. When i hear the ratteling and i go over little bumps, i can hear the ratteling "go" with the bumps. Like the sound will get lower, then higher, and then lower. I dont know how to describe it, but thats my best description. Lol. Any ideas on what it could be? I don't know of anything else that could rattle like a CAT.

Thanks.

 

u have 3 cats on there, 2 pre cats (one for each manifold) then the main, any difference in power?

 

Well, i wouldnt know if there was a loss in power because this is the first v8 dakota i have driven. So, i wouldnt know the difference. But it does seem a little slugish.

 

well i have a 5.9L and i had my flange gasket thats right after the exhaust manifold i had that blow out and it had a nasty rattle at start up and goin over bumps, im not sure whats on a 3.9L if its just a single doughnut gasket or if it has 2 flange gaskets....let the exhaust cool sometime and grab on the pipe and wiggle it...if it has a lot of play and u hear the rattle its most likely one of those or a loose braket maybe

 

3.9 is same as 5.9, just one exhaust tube less on each manifold

 

I have a 5.2 v8. Lol. My user name is from when i had my 1990 dakota 3.9L. But now i have a 99' 5.2L and i dont know ho to change it.

 

oh haha well then i imagine its basically the exact same as 5.9 so i would try wiggling each pipe coming down from the exhaust manifold and see if it rattles then if it does u blew a flange gasket there