Where did this broken bolt come from?

[catera00]

My car has recently started idling a little rough and seems a bit sluggish on hard acceleration. I also am hearing an exhaust leak from the engin area that I never heard before. I looked in theh engine bay and saw this broken bolt sitting there. I am wondering if it may be linked to my problem. Perhaps a header stud broke off? I cant see where it may have come from. Here are some pics:

It has a triangle on the end of the stud

Heres the back


Side


Looks like someone cross threaded it


Heres where I found it. On the Pass. side


Closer shot


I know its pretty random but any help would be great. I had a P0411 code but had it cleared out a few days ago. I read up on the error and I know its cause by the check valve or other components and will trouble shoot it if it comes back. I have cold started the car 8 times since clearing it so I dont know if the code will show up again.

Does P0411 cause any performance probs? The guy at Autozone suggested that the error was from my secondary throttle flaps which are inside towords the back of the plenum not opening enough. He sold me some STP fuel injector cleaner to fix it. But after I thought more about it, I'm not sure it made sense. Any validity to what he said?

Thanks guys

[frank moran]

the stud could be from the exhust manifold?? how it got on the frame rail is the unknown. PO411 is the secondery air inj system and not the plenum switch over valve that Zone referred you to. The AIR system does have a check valve in it to keep exhust from backing up into the air system pump. This system only function on start up and to the point the o2 sensors take over. The check valve looks like a mushroom over on the right side of the engine, trace the metal pipe that runs in front of the water pump over to the R side of the engine, possibly it is bad.

[Marks DTM Calib]

If it was an exhaust manifold stub then somebody has been in there before becuase its the wrong type of nut......

It doesn't look like any nut I know of.....the closest would be the main alternator +Ve connection....