Found Loose Bolt - 2nd Gen 4 cyl

Hi all- Thanks for always sharing your knowledge and opinions on here. I don't post often, (this might actually be my first post) but I've owned my Tacoma for two years now, and enjoy reading the threads.

I was planning to change out the sparkplugs last night on my 2008 Toyota Tacoma. It is a base, single cab 4X4. I was just getting started when I noticed a loose bolt laying on top of the intake. It appears to have come from the hole in the middle of the second pic. The bolt has 3/4" long threads and it fits a 9/16" socket. The hole in the picture looks to be about an 1" deep.

What does this bolt do? Should I be concerned that it had been loose for so long? I've had the truck for 35,000 miles and never noticed it there. Is it a mounting hole for something I don't have on my truck? Or is something now missing?

Thanks!

 

Not sure where the bolt came from.
Here is a pic of my 2014.

 

Do a Google image search for "2TR-FE". The few photos I've found shows that hole to be unoccupied. For example: http://upload.wikimedia.org/wikipedia/commons/5/5a/Toyota_2TR-FE.jpg

In other applications (like the foreign-market Toyota Fortuner), there is what appears to be a fluid fitting installed there: http://www.cars-directory.net/pics/...oyota_fortuner_a1273402802b3619823_6_orig.jpg

Is the bolt actually the same thread size as the hole?

 

Yep, the bolt is the same thread size and turns right in there.

Thanks for the pics. Looks like on most that I can find that is an empty hole... which really makes me wonder where that bolt came from.