Rattling at low RPM

[Wolvrin704]

My car over the past few weeks has started rattling. It seems to do it most when its cold and only at low RPM whether the clutch is engaged or not (at first I thought it might be the clutch). The sound it makes is like when you change gears to one thats too high and the engine bogs down a little and sometimes rattles. But the rattling seems to be coming in the tranny or cats area, almost right under the driver side. Haven't had an opportunity yeat to get under it and look for anything. Any ideas on what it might be?

The engine runs fine, no rattling or detonation coming from it, I know that sound very well and thats not it. I've listened to it idle and reved it up under the hood to be sure.

 

[blubullett]

My oxygen sensors were left loose by a shop once and they would make a nice rattle while accelerating, I think I could only hear it at low rpms. If your h pipe has never been off than maybe you have a cat going bad, or a loose heat shield on one.

 

[8111870]

i had the same thing, drove me nuts! turned out to be the inspection cover on the tranny.
even though the bolts were tight it had enough slack to rattle at low RPMs.
i just wedged some cork gasket material in the spaces and done!