Weird problem while removing Exhaust manifold...
 

Ok i removed 3 of the 4 bolts that held up the exhaust manifold on my 1989 GTU rx7. It's stock and only has 99k miles but unfortunately the owner before me didn't take very good care of it as the rear seal is gone...anyways i get to the fourth bolt and i start wrenching away until i noticed that not only is the bolt moving but also the whole screw thing attached to the housing. WTF?! It seems the bolt somehow melted and fused with it because the bolt will not budge without the whole thing unscrewing with it. what the heck do i do? I don't think removing the whole screw would be a very smart idea...and also seeing as i used a breaker bar and have no access to air tools, I'm stuck. I did use wd-40 and some car cleaner to see if it'll help brekaing the nut free....but we'll see tonight. I was just wondering if this ever happened to anyone else because i see this as an abnormality for obvious reasons.

Happens quite often. Just go ahead and take it out, it's a blind tap hole. I usually just put them back in with tread lock if I can't get the stud and nut apart off the engine.

oh ok cool then i shall do that. thanks for the rather quick reply and look, you have the same number of posts that i do hahaha... well you did =P

Ran into the same situation. It came all the way out in which I ordered a new stud from Mazda and used threadlock to secure the stud. You'll need to use two nuts to get the stud all the way in.