96 420a N/T 5Spd

Well, an answer for this question is going to be a shot in the dark. But I could use any experience you guys have on this.

I have a rattle coming from somewhere around my motor. It sounds more like the drivers side area. Now, I got my transmission rebuilt about 3/4 a year ago. It just started to make this rattle sound this winter. I have never heard my car do it before so I thought transmission. Took it back for warranty and they swear its not the tranny but its coming from the motor somewhere.

Now this rattle doesn't have a normal tendancy. It just comes and goes randomly. It seems worst in the mornings or when the motor is cold. I cannot hear it when the car is driving and it does not make the noise when the motor is reved up. Only at idle.

So, maybe the exhaust is loose somewhere. It is really hard to pinpoint. I understand you guys haven't heard it and that would help, but I thought maybe some speculation on to what you guys might think could help me. Thank you!!