Spark Plug Socket Size?

Well yesterday I was headed out and the truck (2000 5.4 EB Expedition) wasn't running right. It felt like 1 Cyl wasnt running. I took it to Auto Zone. Sure enough p0301 Cyl #1. Yeah it wasn't #4 or #8! I took the truck home and I pulled the COP I didnt find anything wrong with it. I tried to get to the plug but my plug socket wouldn't fit down into the Cyl... I know the socket is pretty specific to include that little insert to get the plug out but the socket won't even fit? It was a 21 or 22mm or 15/16th ". Should I use the smaller lawn mower size socket? Or is there a specific socket for this motor?