I just figured out my wifes XA engine rattle. I got an oil change and they checked the air filter... guess what... when they open the air filter cover and moved it, they also might have moved the fuel lines strapped on the firewall. (since part of the fuel line is right beside the airfilter housing) the fuel line was off the plastic clip attached to the firewall. I just clipped it back in and no more noise! (the fuel line was vibrating off the clip!!!)

Make sure that the fuel lines are all clipped to the firewall

It was driving me nuts trying to find it! it sounds like the rattle was behind the dash and only did it on drive and reverse or with the AC on or when you put the brakes on. Believe me i went through all of the post on the forums. and tried different ways. even attempted to increase the idle. Have someone help you so that they can tell you if the noise is gone!

I hope this helps![/img]