Rattling Noise
 

aloha,
i'm new to the group and i'm glad to be a part of the 986 forum.
i just bought a 1999 boxster last May with 44K miles on it.
recently, i notice a rattling noise when i start the engine especially
in the morning. can someone give me an idea where it might
be coming from? if i am off topic, please disregard this message.
thank you for having me here.

Welcome
 

This subject along with just about every other topic you can or will ever come up with has been covered in depth on this forum. To prevent cross posting and repeats, just use the search function. There's a lot of information regarding this and other issues.
Enjoy your Boxster, and as they say, Drive like the good doctor meant it to be driven. That's doktor of engineering, Ferdinand Porsche!

A suggestion
 

or two.

Have someone near the car try to pinpoint where the sound is coming from when you start the car in the morning when it has been most liable to occur.

Put the top in the service position (see the owner's manual) and remove the cover from the top of the engine (yes, you can do it...it is self obvious) and repeat the "see if you can figure out where in the car the noise if coming from" above.

Wiggle the exhaust pipe (when it is cold).

Could be the heat shield for the cats, exhaust, or any loose part.

Or could be the heat shield attached to the rear bumper, just above the exhaust pipe... mine was. I used some sticky back foam in between the metal and the bumper to stop the rattle. The proper repair would have been to drill out the rivet and re-rivet the plate to the bumper... but I have no rivet gun, so this worked.

Should you find that it's a loose heat shield (not the thin aluminum ones, but the steel ones around your cats) take a hammer and give the offending one a good whack or two.

Fixed my nagging rattle when the exhaust was cold and made me feel really good.

There's nothing that can't be fixed (or further broken) on a Porsche if you have a hammer!

I just installed Fabspeed secondary bypass pipes today - and found that there was something loose in the driver's side secondary cat. In addition to sounding awesome, I no longer have a rattle on startup.