Replacing Spark Plugs
 

Hello, I am replacing the spark plugs on my '97 F-150 with the 4.6. I have replaced 6 of 8, and the last two are giving me the same problem: I can't fit the spark plug socket onto the nut of plugs #4 and #8. Being that those two plugs are at the back of the engine and underneath the firewall, I am unable to see into the well to see exactly what is going on (dirt, stripped plug, etc.). Any suggestions are greatly appreciated.

Welcome!

You may need a special wrench to access those plugs or you have to remove some parts just reach it. Welcome by the way.

Replacing Spark Plugs
 

Almost 100% of the time, it's dirt around the plug. Make a piece of wire from a coat hanger or something similar. Work around the plugs and the blow the dirt out.

I was able to get the plugs out. As said, it was dirt around the nut of the plug. I heard that a few others used a 3/4" copper pipe and cut teeth into it to work the dirt free and blew the well out with compressed air. I gave it a try and it worked. Thank you all for the welcomes and suggestions.