2004 4Cyl. NA, I'm changing the spark plugs for a coworker, but can't get the lower left hand bolt off of the upper manifold covering the plugs/wires. The head is perfectly fine, and it turns normally when trying to unscrew it, however, it just doesn't give. felt the bottom of the bolt, and it's rotating as well. Maybe the threading is bad? Any ideas on how to remove this clumsy bolt?

 

Plastic manifold...Brass inserts for nuts....

You are sorta screwed.....What I usually do with them is an Impact gun and the necessary adapters, and just spin it full throttle until something gives.It will usually "Melt" its way out with the insert still attatched...if your lucky enough to NOT hurt the intake...a nut and bolt thru the existing hole works well....

If not...replace the lower manifold...