Trick/tool to remove hidden intake manifold allen bolt?
 

I am trying to remove the intake manifold off of the head as a whole unit but that last hidden bolt underneath the t-stat housing seems impossible to get off without splitting manifold in two. A fuel pipe is right in the way of any tool I tried, and can't even get to the bolt to move that out of the way. Maybe a special swivel allen socket tool? Do I have to split the manifold in two to gt to this bolt? Thanks!

it's notorious for the head of that bolt stripping out as well so be ready for that. I took my upper plenum and fuel rail off and then access to the hidden bolt is no longer hidden and I got on it with a3/8 drive with a 6mm Allen socket. since it's so easy to strip it I would do it again that way if I had to but it's probably best to find the same size and thread count bolt in hex and install that instead, I should have done than when I put mine back on. If it does strip some people have had success with hammering the back end of a screw holder for an impact driver the (kind that would go into a battery operated screw gun/Impact driver) into it then grabbing on to it with a 1/4" wrench or jam a security bit into the end of that and connect it to a breaker bar. . other people have reported that they cut a notch in the end and got on it with a flat head but I'm not sure how effective that would be considering how stuck that bolt can get.