Sounds like you all had fun. I thought that spark plugs were to be changed every 60k miles. My worked fine all the way to a 100k when I did valley pan, and while there did the plugs.

I do not think there is a way to get that (driver side back) plug out without climbing onto the engine. I did have a friend hold the hoses as I was "cursing up a storm", I mean removing the spark plug coil and plug itself.