Hi All,
I'm new to this forum, but have been lurking for a few years. Did a search but can't find anyone with a similar problem.
I have an xc90 '04 that has been rattling under the front of the car for about a year. The noise is driving me nuts. My mechanic said it might be the cat, but can't tell 100% by the noise. It sounds like a metal can with the top popped off and rattling in the can when you shake it. Most people hear the noise when they decelerate but my car does it when I'm idle or accelerate up to 20-30 km. The noise gets very loud when I step on the gas and go up to 5 km. After that I can't really hear the noise.
Anyone have this problem before or can weigh in on my problem?
I'm looking on Ebay for a new cat that should run me about $300 but I just want to be sure before I purchase. Any help is greatly appreicated!!!

 

i'd take the cat off and shake it before buying a new one. it could be a loose bracket or shield or something else.

 

just wanted to update that my mechanic found the awful rattle, it turns out it is the driveshaft in the rear. Once he was holding the driveshaft the rattle went away.

 

Glad you found the source of the noise. Also, a bad cat will give you a code.