Rattle noise under dash ??

[TracyRGraham]

So I thought the rattle noise was coming from maybe the engine compartment but I cant find anything there. What I dont understand is that it is not a constant rattle, like in a rattle from a loose anything. It makes the noise when you accelerate with a load. I cant pinpoint where it is coming from exactly. I thought it was coming from maybe under the car like the exhaust but I went all through it and nothing. Has been making the same noise for some time and I thought it might get louder and then I would find it but no. I tried disconnecting that fan deal in the panel in the floor of the passenger side, nothing. All I can tell when driving is that it is coming from the passenger side. Driving me nuts! And turning the radio up doesn't work either, I still here it.

 

[long Tall Sally]

when the catalytic convertor starts to go it can rattle like that. you may have to have some one outside and then torque the engine in gear to get it to rattle. Takes a combo or heat and rpms to get it noisy. they usually sound like marbles In a can but I have not actually heard one out on an XLR but have heard them on lots of cars.