This suburban has 5.7 v8, I recently did the intake manifold gaskets and I found this wire that possibly needs to be plugged in I don't recall ever unplugging it but it's there and I can't get it off my mind I can't find it in any of my manuals and starting to get frustrated so i came here to hopefully get some a solution. Thanks in advance. If I need to get some better pics I'd be more than willing

 

Hello Rusty
It looks like it is the connecting wire for the cylinder head temperature sensor? Which is in between the exhaust manifolds. I say manifolds as one side has a sensor and the other side a blanking off plug. I have seen these swaped around at times?
Take care
John