The bolt that holds down my #3 cop will not come out for anything. It just spins whether I try to tighten it or not. Nothing. 2001 f150 supercrew 5.4

 

Someone cross threaded the insert in the intake manifold.

 

yep...be careful ...it's a metal insert in a plastic intake manifold.. You may be able to get some type of plier in there to hold the insert from spinning. Maybe a little pressure with a screw drive between the COP and insert.. but, like I said be gentle ...the manifold is plastic.

 

My #5 bolt did that. the metal "nut" insert that is set in the plastic manifold breaks free and spins.
My fix, hook it up to a drill on high and get it really hot then pull it out. Worked great for me, and used some epoxy to re-set the nut back in place.

 

Nice...