Sounds like a damn 5.4 Ford to me

 

does that plug thread into any other cylinder?

 

That's actually the plan to use first. And if that fails, then the helicoil tap. I hope it doesn't come to that, but if it does so be it.
And it's not the plug, it's definitely the port on the cylinder head.
Plan is to give it a shot tmw, I'll let you guys know how it goes.
Hah keep your fingers crossed for me. And thanks again guys for continuing to make Cherokee forum so awesome!

 

Whew.. Ended up using the thread chaser - 14mm in case anyone ever needs to know. Just took my time and gently in and out. Grease a little each time. And after a little bit the threads cleaned up, and the plug went in.
Thank the lord!! Hah

Here's the one I bought and used. Just inserted an extension in the one end and hand spun it.