I had this happen on a dirtbike once and it came right out with a set of easy outs. Seems like on the truck it would be a lot harder to get too though.

 

Not yet Tarner...not budging. Thought I was gonna snap the ez out so I sprayed it down again. Just trying to take my time so I don't *** it up even more. I don't 'need' the truck 'till next weekend due to having a company truck for work. So I will try babying it out. I didn't use the Mapp gas today. I tried the propane and apparently that just ain't gonna work. Smoked like a bastard right at first because of the penetrating oil burning off.

 

Sounds like it must be cross threaded in there if it's that tight.

 

Mike one other thing to try is to start the engine and let her reach operating temp this will heat the area hotter than the mapp gas will. Ps unplug the injectoer to that cyl so it wont gas up while running.You mentioned leverage in your post you want to be careful here cause leverage can be your worst enemy. If you use a ratchet and extension be sure to use both hands on the top of the ratchet to equalize the tourqe force thats why I said buy the rigt handle to use so you can equalize the force on both sides this is most important . You want to maintain the same torque on both sides the tool to keep it from binding and snapping off. Another thing to try is to have someone tap very lightly on top of the handle with a small peening hammer to create a vibration , this will help loosen the plug base. Good luck and remember wht I told you dont get in a hurry some times a steady pressure on the plug will make it loosen just as easly. terry--------tboss

 

Got the son of a bitch out today...smooth as butter...
I never even had to take the heat shields out...
The way I got it was by soaking it for a few days with liquid wrench. I also had a 12 inch piece of pipe that was the same diameter as the spark plug was. I set it on the plug and just started tapping it with a ball peen hammer for a minute or sojust to try to get the rust to vibrate and break the bond, not super hard, just a light rap. Then I would spray it again and let it sit. I did that for 3 days and gave it one last shot today and then tried the spiral ezout. I used a 3/8 socket to hold the ex out and a 3/4 drive ratchet with the 12' extension and she spun right out without too much pressure.
I really lucked out I think. I was worried about heating the block with a torch. Luckily I didn't have to.

 

Well your lucky.. I had 5/8 of mine the exact same way. Just use a **** load of heat and EZ-Out!!

 

I had never had it happen before and hopefully never again!!! Just for the ****s of it I took another one of the plugs I had already pulled out and just scored it with a hacksaw where the other one broke and I couldn't believe how easy it was to snap. I only used a 5/8 open end wrench with the plug in a vise and she snapped with barely any pressure...
Not sure if it matters but it was a champion plug. I don't know if they are thinner or if it is just the design of that particular plug...