Well I think the ims is going
 

Ok I have a 99 2.5 boxster 59000 miles trouble free serviced every 5000 miles
untill the other day noticed at idle a rattle sounds like metal rattling against each
other. Not like a rod or main noise.Sounds like a wore out belt tenioner rattle but
inside the engine. No noise when cold and only at idle but seems to be inside
engine down low as far as I can tell so far.Appeared overnight as far as i can tell
I dont have alot of expertize on these engines . Alot of experice on 944 engines
great engines so I am not to happy with this design. OK whats it sound like IMS
bearing . I am not driving it now but do I check futher with the engine running
and chance it or do I just get ready to take the trans out and check? Thanks alot
far help with this matter

If you catch it now, before it totally fails, the engine can be saved. Once it fails, you have a boat anchor, period. To access it, you pull the trans, clutch and flywheel..............

It's possibly a TO bearing. Does the sound go away when you press the clutch in?

No it does not change with clutch in or out .Also tried loading the trans alittle to see if it would change but it didnt.

If it were me I would not start / run the engine any more, the bearing may seize like this one:

http://www.youtube.com/watch?v=LlWMlimt9w8&feature=related

IMS situation explained:

http://www.youtube.com/watch?v=xvLRMGs-Ti8

Good luck.

Not sure what part of Bama you're from, but Jake is in North GA, and I'd think about a little trip for the IMS upgrade even if your IMS turns out not to be the problem.

Better safe than sorry.

Good luck!

http://www.flat6innovations.com/

it could be the timing chain tensioner worn through or broken ,i watched a youtube clip claiming its common and people are just thinking its the IMS ,but infact the IMS was in good condition on this one they took apart ,but the valves had hit the pistons aka IMS style

Check your oil filter to see if you have any evidence of a problem. If its the IMS bearing which is sealed you may not have any metal but other problems could possibly be found